I have never had the opportunity to play any of the G-series adventures or the remakes, or really use giants in general (though I have often planned to). I blame them being understandably mid- to high-level threats, a lofty peak that my groups have only achieved a couple of times. In fact the only time I can recall dealing with giants--specifically frost giants--was a mid-level 2nd Edition campaign.
Speaking of older editions, most of the flavor is expected holdovers from earlier editions: stone giants shaping stone, storm giants controlling weather, cloud giants living in castles on clouds, hill giants being stupid, and so on. There is also some new stuff in the mix, such as hill giants ranking each other based on who can eat the most and cloud giants mining silver from clouds.
In addition to a easy to reference bullet-list of giant traits, you can also play guess the giant here.
The only ones I am not positive about are the cloud and storm giants (which I assume to be A and B respectively). Spindly legs aside I think they are mostly okay, though the fire giant's armor seems...sleeker than what I would have expected, I guess (and I assume the loincloth is made of something that is immune to fire?). Personally I would cleave to Wayne Reynold's depiction from Secrets of Xen'drik: