Arcane Power is the latest power source-specific supplement released by Wizards of the Coast, adding new options for the bard, sorcerer, swordmage, warlock, and wizard. Like its predecessor Martial Power, each class gets their own individual chapter, which adds new class features, powers, and paragon paths to each class. There's a section on feats, and in touting the new tome implement a magic item section that offers a small selection of magic tomes. Its a great book with a lot of great stuff to offer any arcane character (except the artificer, who gets to wait for Eberron Player's Guide).
Before I dive into the classes, I want to mention the sidebars. This book is laden with sidebars in each chapter, most of them talking about what races would commonly pick whatever class you find yourself in, and why. I think these are useful resources for new players or players looking to try out a new class (or just want to try an unconventional race). However, some also explain some of the new stuff, and I found the ones on illusion and summoning magic to be particularly interesting. I'm sure a lot of people hate them for taking up valuable page space, but not myself.
Bards are one of the new kids on the block, receiving a new virtue that lets them boost an allies defense by 5 against an attack. Its an interrupt, which makes it similarp-but-better than the wizard's shield utility since it can apply to any defense and grants a slightly better bonus. Otherwise its a big chapter with more bard spells. What makes it interesting is that many of them require ranged weapons, making an archery-themed bard viable at this point, and the euphonic bow paragon path further emphasizes this build by letting you use a bow as an implement.
Sorcerers get two new spell sources: cosmic and storm. Cosmic sorcerers gain benefits that change with each rest you take, which represent reoccuring cosmic cycles. Some powers let you change it to one of your choice, or set it to a specific one. I already pegged sorcerer to be a class that appeals more to the "dedicated" crowd, and this just further reinforces the fact that if you are a casual gamer the sorcerer is probably not for you.
Storm sorcerers gain lightning and thunder resistance, and can push enemies when they crit them. Its easier to manage that the cosmic sorcerer, so if you are itching to try one but want to avoid bookkeeping you could certainly do worse.
The new powers obviously cater to the new spell sources, but they supplement chaos and dragon sorcerers as well. My favorite goes to wyrm form, which is a level 29 spell that lets you take the form of a dragon, granting you three new attack forms while the spell lasts. The reason why I like it is because you take the form of a Huge dragon. So...yeah. Oh, dragon sorcerers get an attack bonus with all the attack forms granted by the spell, to boot.
Swordmages get a new aegis that lets you teleport a monster and also disorient it so that it grants combat advantage. The swordmage saw some expansion in Dragon, but otherwise not much. The new class feature is interesting, and it gets a bunch of powers and paragon paths, but not much else. I'd say this is the most lackluster of all the class chapters, but probably because I dont play a lot of defenders anymore, instead getting shoehorned into the leader role.
Warlocks get a new pact (vestige), but not much else aside from powers. Its not surprising since they already got a lot of love so far in the form of Class Acts articles and the dark pact in Forgotten Realms Player's Guide. Even so, they get a lot of new powers in this book that are tied to all five pacts that they can now pick from. Likewise they get some very interesting paragon paths that work with each pact as well as some generic ones.
Wizards, I think, see the most improvement across the board. I felt that wizards were playable originally but seemed a bit pruned when compared to bygone editions. In 2E and 3E you had a bunch of spells that did a lot of (often useless) things, existing mostly to justify how a NPC might conjure a magical disk to carry luggage, or an invisible butler to serve drinks. The most common archetype was the blaster-mage, capable of dealing high damage to a high concentration of targets. This is the one that 4E emphasized the most, though to be fair there were plenty of utility spells and rituals to give the wizard some wide coverage.
Dragon articles expanded them a bit, providing some thematic illusion and necromancy powers, but Arcane Power ironically blows the doors wide open by providing a heap of new illusion and summoning powers. There're three, count 'em three, new forms of implement mastery to compliment this expanded selection to boot.
Orb of deception is ideal for tieflings, since its keyed to Charisma. Once per encounter if you miss an enemy with an illusion attack, you can redirect it to another creature instead, adding in your Cha bonus to the attack.
The tome is a new implement, and they give you two options to play with. Once gives your summoned monsters bonus damage, and the other lets you drop an encounter attack spell into it that you can cast by burning an encounter attack of an equal or higher level. You only get to change it when you level up, but it adds a bigger degree of flexibility to wizards when you consider their spellbook class feature.
The best thing is that they're globally fucking useful. Determining how effective an illusion was could fall to DM fiat, assuming that the monster could even be affected by it in the first place (I'm looking at you, Undead type). Also, if you specialized on illusions you probably wanted to go about problem solving a "different" way, which is another way of saying that you wanted to trick a monster with some trite illusion and hog the spotlight. Kind of like how only rogues got to tackle locks and traps, except that its more like playing Metal Gear Solid 4 where everyone shows up hoping to play but has to watch and illusionary movie.
Illusionists now actively participate in the challenges instead of (maybe?) soloing them through a convoluted scheme that has to get bantered back and forth until the DM finally caves. They mostly focus on psychic damage and their utilities do what you expect by allowing them to conjure up illusionary terrain and obstacles. All in all a major step forward over prior editions and its become a very attractive choice for my players.
Summons are likewise spells that you would want to take, since you can summon things that arent several levels weaker than the weakest crap you'd fight for your own level. If you didnt play 3E summons worked like this: you took an entire round casting the spell, and at the start of your next turn a creature would appear and you could make it attack. Now, imagine that you're a level 3 wizard, which means you can only summon stuff that is level 1. Now imagine how in the hell this thing is going to achieve any purpose aside from provoking opportunity attacks or just trying to get in the way. Dont get me wrong, I really like summoners and the concept behind them, I just rarely tried to play one because I didnt want to be about as useless as the bard.
I'm sure Red Jason would love to tell you about how he summoned a shitload of devil spiders only to have them all die in one hit. In the same round. Using his highest level summon spell.
Since summons have stats based on your own, they can actually survive and contribute more reliably. I've got a fire-base tiefling summoner in Adrian's Scales of War game, and it was fun to be able to finally summon a monster that landed a hit. Several times. In the same battle.
Now that we're done with the classes its time to get to the feats. Chapter 6 rolls out new feats for all classes, for all tiers. They each do their part in modifying/improving the way class features work or by tying racial characteristics into classes (such as drow gaining combat advantage against cursed targets), but best addition by far are familiars. Yes, familiars. I've really never liked familiars until now. Sure, they sounded neat in concept, and rarely could provide some form of comfort in social roleplaying, but they were mostly just worthless mobile XP sinks.
It takes some time and money to get one, and if it ties its sure to be remembered not for the fond memories but for the assload of XP (or perhaps a Constitution point) that it takes to the grave. Oh, and in case you are feeling particularly risky, you have to wait 100 days or so to snag another one.
Any arcane class can snag a familiar with a feat, and there's no charge. They are formed out of arcane energy and actually give you benefits since they cost a feat and all, though the better ones require that you keep your famliar active. Active mode lets your familiar run around and get attacked. If you are feeling protective or just dont want/need the active benefits, you can shift it to passive in order to render it invulnerable from harm. Best of all if it dies, it reforms after the encounter without any lingering penalty.
Every familiar has something to offer, and the problem with me is that its hard to pick which one I want.
There's a section on customizing your familiar's appearance (within reason) and to determine how it enters passive and active modes. Good stuff, as it adds a lot to a formerly underwhelming class feature. Finally, there is a small section on feats that let you boost your attacks, protect yourself from harm, or communicate telepathically with it.
Next, we get to epic destinies. Almost all of them are for generic arcane classes, though there is one for the swordmage, fey warlock or fey character, and wizard. The parable is a master of illusions that considers existence to be merely a story that she has learned to write and rewrite for herself. You get to avoid difficult terrain, ignore damage from missed attacks, and appear elsewhere when a monster tries to hit you, but its the base concept that makes it so appealing.
And then we arrive at the end of the book. Magic tomes, new rituals (of course), and some arcane backgrounds round out the last part. This is an excellent supplment. Almost everyone in my group bought a copy (except Jen, but she's poor), even the guys that dont seem to arcane characters. I think it shows a major increase in quality from Martial Power, which makes sense since it was the first of the power source books. I'm already using a good deal of it for my bard and wizard, and given the chance would jump at playing a starlock or sorcerer (probably cosmic, since it amuses me the most).
I'm not exactly a fan of rating systems, but I think that they really help you determine at a glance if something is generally good. For now, my recommendation is to get this book if you like arcane characters on the whole. If you like only one specific arcane class, I'd still recommend it unless you are only into swordmages. That section is pretty spartan and you might not get your money's worth out of it. That being said, its got a decent chunk of content, I just think it got the short stick. Hell, get it for the familiars alone.