Traffic is the bugaboo these days for US players.
There are actually a lot more sites available to US players than any of us know. Many are subscription based sites, meaning you pay a fee up front every month and then play your heart out. These are primarily tourney based sites.
For ring play, our options are more limited,
Merge, Bovada, Revolution, WPN, and Lock are mostly available to US players.
Lock has payout problems, so don't go there.
WPN has proven payouts in pretty quick fashion, as does Bovada. Have not read a recent merge payout report, but I got an email promising speed. Some revolution skins pay fast, others don't. None will approach the old days when Netteller worked. For US players the fastest is a couple of days to the WPN debit card. For checks, under 2 weeks is normal, except at Lock, which has not had a recent report that I have seen.
Find the payout reports thread for recent results.
I will guess the consensus will suggest Bovada, or Merge.
Game variety drops with traffic. Bovada and Merge have higher traffic, and thus a wider variety of games.