Oops, sorry. I actually don't have direct experience with them.

I personally only use coinbase and btc-e. Other random folks I see online[1] seem pleased with bitstamp and I've never heard anything bad from coworkers who are into bitcoin that I talk to. My point-of-view on these bitcoin exchanges is pretty much they're all great unless you can find an overwhelming amount of negative opinions about them... or they're brand new with no history to judge them on.

1. http://www.reddit.com/r/Bitcoin/comments/1m2upn/going_to_sta...