Indaba seems to be a more social ACIDplanet. I signed up for Indaba a while back for the Scott Pilgrim remix contest but never entered, so this is my first time seeing how this all plays out. I used to be prevalent on ACIDplanet years ago when Vrenna was hosting the Tweaker remix competitions. There were popular people who went around commenting on everything to get listens/plays; they just enter every single thing and have their following comment/circlejerk about how great it is even though it's honestly a mediocre track. With Indaba, it's more of the same, except now there's a voting system in place to actually move tracks around. Indaba's layout is good for people to randomly and easily go through tracks and listen/vote; I've barely promoted mine and it's getting plays/votes/comments/etc (not sure if that's ETS at work or random people though). I think it's better than hosting it on remix.nin.com, because The Social Network remix thing resulted in people going around giving out zeroes to every track and lowering score averages.
I'll also echo what people are saying here about the overall quality. I went through and listened to several "popular" tracks and...yeah. But, different strokes for different folks. However, it's important to keep a level head about it. If you're proud of your own work, that's what counts. It shouldn't be measured by hours of time spent or votes tallied. It's nice to feel validated by comments and whatnot, but it's also good to challenge yourself with these sorts of things, take criticism in stride, and learn from the whole experience so as to apply it to other competitions/personal recordings.