I've tried playing in primedice, freebitcoi.in and bustadice and so far primedice has the most highest faucet claims and so far good betting site though I don't place much on these casino faucet but I enjoy playing on this 3 sites I haven't tried other casino but I think as long as the payment is good and fair all casino are good place to gamble and have some fun.
I think if you are active on their site and place quite high rank, you can get good faucet, but most people are trying to make a new account im order to gamble away some free money without even make any deposit, which is forbidden on each site. So if you just focus on one site and wagered some amount or get into high level, you can claim pretty big amount of faucet