My favourite one is still bitvest and betterbets. Although I keep losing on both sites but I still enjoy playing there and hope for recovering everything 
the best dice sites is sites who offer free satoshi (sitea with a decent faucet) and a lower edge.
There is many sites that offer a good satoshi too not only betterbets and bitvest. Primedice offer good satoshi too and there are still many more out there. You need to do more research