I win routinely at online casinos - and some times in the low four figures. So I am somewhat an "expert" on this. Based on my experience, I have a reccomended list and a non-reccomended list.
My reccomended list includes casinos that use Cryptologic software. I have found these to be the most fair and beatable when betting large hands up to $1000. I know because I've won some of those.
So Sands, 1on1, Omni and William Hill would be good choices.
As for sportsbooks with casinos, my favorite is Pinnacle. I also feel very comfortable with their java software, I also have won high limit hands, have also won consistently if not always, and you get a 0.3% rebate on your total action win or lose. If you are going to play online at a sportsbook, this would be my number one choice.
Number two is WSEXY. Once again I've won my share of max $500 hands, feel comfortable with their java software and while you don't get any rebate you do get a fair game in my opinion.
Third one is Carib. Feel comfortable with the java, have won big hands before, and get a rebate. But this one can be streaky. I have found very dramatic swings between winning and losing streaks can occur. I wouldn't feel comfortable trying to BLOW here because of that, but for the short, all or nothing sessions, they are fine.
Those up top are basically the only casinos I play at. I think I will have my casino access disabled at any other place I deposit. That's more than enough and I don't want to take a chance on a place I don't know.
Now these are the casinos I don't feel comfortable at. Any casino with Microgaming software like Intertops. If these sukkers aren't rigged, they are almost impossible to win at and especially when you up the bet. I also don't trust Boss casinos such as Bowmans and BET365. For myself I just haven't had any success there and don't feel comfortable.
Overall I think there is a greater chance I win $100,000 at a casino than with a parlay. The Crypto joints I mentioned are probably where it will happen. With fair BJ and up to $10,000 BJ limits this shitt could hit on Any Given Suicide Sunday Al Pacino.