ACR/WPN seems legit but lots of nitty bonus/rakeback grinders and bots there. But does have rakeback.
Bovada/Bodog/Ignition even though their software has taken a nose dive was reliable for payouts as recently as this time last year. (I have a May 2016 check from them which cashed no issues). But no rakeback.
intertops is often overlooked but is solid, accepts Bitcoin, their check cashout fee is a bit high but nothing absurd, software is dated but smooth. Has rakeback too.
IMO Bovada/Bodog/Ignition is best for freezeout (aka normal) MTTs while Intertops and ACR are probably best for cash games (although ACR has better MTTs than Intertops but Intertops is more rec player based than ACR in cash games).
Bovada/Bodog/Ignition probably has the highest traffic followed by ACR and then Intertops but you sacrifice player notes, usernames, and rakeback for that traffic.