Crypto-games offers a small pool of different ways to gamble with: Dice, Slots, Blackjack, and Lotto (where you compete against other players, buying tickets like a lottery) It accepts seven different altcoins: Dash, Doge, Ethereum, GameCredits, Gridcoin, Litecoin, Peercoin The UI is a bit dull, and the blackjack game is ridiculously loud with the card sfx. Their dice game has a house edge of 0.8%. The rolls are at a fast speed. They also offer a progressive faucet that increases up to 0.0002 BTC once you pass requirements. To deposit, you need one confirmation on your transaction, and to withdraw, you require two confirmations on your transaction. Overall, it's a good casino, but much can be improved.
Sportsbet.io is a sportsbook that has a vast variety of markets and games. However, the UI leaves something to be desired as it's not as easy to navigate as one would like when they want to quickly place a bet. A small issue is that occasionally a market closes but is still displayed as open with the odds. The minimum bet at sportsbet.io is 5 mBTC. Deposits are instant and withdrawals are quick as well. Overall, it's a good site but needs some improvement.
Albeit Satoshidice was one of the initial gambling sites, it does not in any way mean that it has stayed great. Its house edge is much higher than the ones you can get pretty much anywhere else that offers dice, though satoshidice does offer promotions (only if you have the bitcoins to wager for them). Other than that, they are lacking. Satoshidice also does not support users from the US. You should only seek to invest here, or play if you have a lot of bitcoins to gamble with.
Nitrogen Sports at its current stage is pretty good. Their sportsbook covers a wide array of options and markets, though not always all of them. For example, I'm unable to bet on 2nd half and players being sent off (but that isn't too much of a problem). They include a dice game, blackjack, and poker. The minimum bet for blackjack, however, is 1 mBTC and the rulings make it a bit more difficult for the player to win than on other sites. Their poker has an hourly freeroll and many other freeroll opportunities, and a moderate-sized community along with a rewards system. Overall, they're recommended but there could be more to offer.