I can confirm Hashnest and Genesis Mining, i have to check better bit-x but in the first view looks legit.
i agree with Hashnest but not on genesis mining. bit-x looks like trusted too coz they are under BitFury are they confirmed it AFAIK
Im not trust genesis mining, "lifetime contract" is very possible running ponzi scheme
also if you calculate "the fee" and "reward mining" different if you calculate with mining calculator