I feel I have to chime in with some DKC3 defense here. On a recent play of DKC3, I had a lot of fun finding all the bonus barrels in all the levels and clearing it to 103%; a lot more fun than I can remember having with DKC2, as great as that game is. The level design is still brilliant, the music isn't horrible, there's no shortage of challenge, there aren't really any bizarre design flubs.
I don't think it's that DKC3 is a less good game than DKC2, it just has a very different flavor. Maybe it's the lack of a pirate theme, maybe it's the more 'Northern,' brighter environment, or the non-Wise soundtrack. Maybe people just don't like Kiddy.
I stand by the opinion that DKC3 is as good a game as DKC2.