Okay, I’m not sure, but as fas as I know the biggest players have the most profits. So, I think that biggest profits may be given only by giants like HashFlare or Genesis. They are quite old and relatively safe, so users like them. However, middle-size cloud servers like CCGMining should offer extra features and they do. Bonus codes and promos are familiar for users of such sites (you can check this –
http://ccgminingcode.com/). I don’t know for sure, but I suppose that bonuses may bring middle cloud miners additional income.