I play at Bovada
. The customer service is great and i hear cash outs are one of the fastest. I would definitely recommend this site to you if you can deal with the fact that you are playing against anonymous players..
ACR is also a good site with great customer service. I hear their cashouts are fast too.
Carbon is another good one, dont know really much about it besides that it gets a lot of traffic
Hope this helps! If it didnt im sure other members can help you out. And there are plenty of other threads on this topic.