Casumo is my all time favorite. I have been playing on Casumo ever since they launched. Their layout is super simple and really easy to navigate. Also the game selection is really wide, and they have really fast withdrawals. I also like the races at Casumo, you can win some extra freespins/money while playing.
Rizk is another favorite of mine. With a really good welcome offer and wagerfree reward system, it became one of my favourites instantly. Super fast withdrawals, polite support and all the games I want to play. And every level you gain, you get one spin on Wheel Of Rizk, where all the rewards are wagerfree, or you can even hit the jackpot with pure money.