Maybe its much better if we narrow down the search by asking which one have scammed their users because if we ask who is honest, everyone will surely raise their hands, but if we ask who has been accused and have a confirmed scam, one, two or three will slowly put down their hands.

I guess among the four categories being mobile friendly is the most important. Being on the move and always on the move is what people are nowadays and what they always have in their bag is their smart phone or a tablet. Access to a laptop or desktop maybe hard or limited to others so going mobile is a good idea. Eye candy games, nice games depends on the user perspective. One user can survive 1 day of playing just dice games or maybe a player can be happy with just dice games but other might want to play other games occasionally.