A good alternative is PadMapper.com. Somehow, they are able to cut out a ton of crap from the over postings. Worth a shot if you are looking for an apartment.
Padmapper is phenomenal, but craigslist sucks so bad, that it ends up just being mildly useful. The ability to constantly and repeatedly relist the same (often fictional) property really depresses me. So easy to fix, and would make life so much better for users, yet, it will never get fixed. And yet, craigslist continues to dominate so many markets. Why god, why?