They're expanding their selection all the time. Bad movies? NO WAY! We're talking classic 90s Action flicks that were AAA titles in their time. New releases? Not so much - 2012 & Surrogates just became available... but titles like those are rare.
The real value? TV SHOWS!!! Old stuff like A-Team, newer stuff like Bones & other stuff I wouldn't know if is good or not (I don't watch the newer stuff on TV), along with classic cartoons like Rocko's Modern Life (added recently), Ren & Stimpy, etc.
You can also catch about every season of South Park and a lot of good comedy specials from Comedy Central. EDIT: Oh, Chappelle Show. A lot of people are into that, so I should mention it's available.
The service is good for watching random stuff you would never bother renting a physical copy of. And you'll probably find some "crappy" title you actually end up enjoying a lot.
I just wish their Anime section wasn't so piss-poor!