As far as I can tell, Twitter is hugely dysfunctional and has literally contributed to at least one friend's mental decline. (Twitter seems much closer to single experience since you automatically get everyone's comments).

Facebook seems much more "what you make it", meaning it can be as bad as Twitter if you choose the wrong friends, wrong groups and wrong approach or it can be a place where you meet people with similar interests and filter out the noise.

Especially, you have this effect "everyone hates Facebook" but that everyone is distributed between people wanting Facebook to censor more (and as they'd prefer), people wanting Facebook to censor less (and especially not bother their bullshit), and people using Facebook as a stand-in for social networking or being on the Internet, or just talking with people you don't know very well.