Bookmaker is the most established U.S. facing book remaining. My Bookie opened two or three years ago I believe. There has been good feedback with them, but two or three years is still new.
I actually got a call from MYBOOKIE regarding my play about a week after I opened an account there.
A) I've never got a call like that from a book before
B) It's a good sign for their longevity and shows they're vigilant
MYBOOKIE is by far the easier of the two to beat, but if you're just someone who bets for fun, I'd go with Bookmaker.
Also, if a guy giving sports betting advice is getting kickbacks from the place where his clients may be potentially making bets, what does that say about the guy?