I make most of my income sports betting (not promoting) and have since the early days of online gambling. I browse this forum from time to time because I am also a full time affiliate promoting mostly online poker.
fwiw here is my take:
If you care about your players then this is the list of sportsbooks which accept American players and are good to promote and will treat your players right.
Also including my personal grading from player prospective:
Bet Jamaica A+
TheGreek A+
5Dimes A-
Bookmakers A
Bodog A
Skybook B-
JustBet B
Intertops B-
Add WSEX and Matchbook also to this list as A but they only work affiliate deals with authority sites.
Sportsbook.com I rate a D
BetUs.com I rate a F
(Along with all their properties)
The other book mentioned Bet Empire I’ll toss in Sports Interaction and put them in the same category. These are C range sportsbook, they are not scum like BetUS or Sportsbook.com and are decent but rate below the first 10 sportsbooks I mentioned in this thread.