I haven't personally dealt on it, but know three people that have found good deals and had fine transactions. It is pretty much just like craigslist.....but with better listings
never dealt on it either, but there's also a new classifieds site that danp (pafoa's founder and owner) create a few months ago too.
http://www.armsdealer.net/
I guess that "Armslist" thing kinda worked out
after all.