I am also in the US. I would use Justbet but haven't used the others before except bodog and didn't like the
lines or customer service.
Jazz was a great pro book 5 years ago . Then the crisis hit and Jazz went down to dark side of the moon. They owned lot of money to players and had liquidty problems , add terrible CS and you will get the picture. I miss them but I don't think they will ever be the same again. They accept US customers and this market badly needs pro oriented book after Greek and Macthbook left US... As for now Jazz is just an vedgetable. BetOnline seems to have payout problems that BM does not have. BM is just bit bossy and slow but it will pay. JustBet is for pussies! They are so vanilla that they will limit you after you win your first $100 bet... screw that!