By sport
A book that is good for football can be poor for tennis. Each sport is a different board, and the pages here look at books one sport at a time.
Why the sport changes the answer
Books don't put the same effort into every sport. On the big American leagues most books deal a lot of markets and take large bets, because the money is there and so is the information. On a smaller sport the board is thinner, the limits are lower and the number is often less carefully made (which can cut both ways for a bettor who knows that sport well).
Live betting differs too. A book can run a fast live board on football and a slow, thin one on tennis. Props follow the same pattern: deep on the games everyone watches, thin elsewhere.
So I'd pick a book for the sport I bet most, not for its name, and I'd look at its limits on that sport before anything else. Each page in this section takes one sport and says what to look for in a book for it. Whichever sport you bet, the same rule holds about money. Decide your bankroll first and keep each bet a small part of it.
Pages
Football betting sites
Horse racing betting sites
Esports betting sites
Soccer betting sites
Nba betting sites
Ufc betting sites
Best college football betting sites
Best college basketball betting sites
Super Bowl betting sites
Tennis betting sites
MLB betting sites
Golf betting sites
Entertainment betting sites
NHL betting sites
Political betting sites
Boxing betting sites
NASCAR betting sites
Cricket betting sites
Table tennis betting sites
Formula 1 betting sites
Rugby betting sites