As far as i've concerned - every poker btc site sucks hard. Which is kinda unfortunate really. They all look very amateur and un-safe (security/collusion/superuser)-wise. So i would not recommend playing for any significant amounts there ever. Maybe it will change someday though.
Looks to me from reading these sites that a few are very safe, the reason is they take bitcoin, create an online chip account, then the user can play with casino chips, then they pay out from an offline vault and they have no program to download to play.
So the sites doing btc this way that isn't 'instant' but takes the btc to a vault will probably never be hacked, at least their vault. Now a players account may be hacked but then his account isn't btc so the casinos can stop fraud if alerted by user or if they use a double withdraw system.
Example, player funds account and plays and for some reason his account is hacked, the hacker then has to try to get casino to pay him, but the casino pay the account owner that funded the account. So this method looks very secure to me.
The sites you have to download a closed source script, no way, the sites that have you playing online, well they could be hacked.
The sites storing btc off line and using their own chips, those appear to be very safe.
These are the same type of safe casinos
www.SealswithClubs.euwww.1player.comwww.ibitcoincasino.orgFrom what I've been reading in this section