To add to the list I have been using coinex the last couple of days and have had a very pleasant time on there. It has the usability (GUI) of cryptsy with a decent selection of altcoins and decent volumes, its also very snappy in my experience and for better or worse it has a trollbox - can be entertaining as long as you take any advice from there with a fist full of salt. I have seen some talk of slow withdrawals even though I haven't had that problem myself (I did see a comment in the trollbox yesterday saying it was fix now though) and it is stated to be in beta so a WIP warning I guess and I cant comment on their support yet as I haven't needed to use it. All in all if they add a few more coins and pull in a bit more trade volume this has potential to be a cryptsy killer IMO... fingers crossed from me!