depends on what you want and how much you are willing to go out of your way. By far the best is Sportmarket Pro which is what I'm using for 99% of my betting but it's web2 with the option to deposit in BTC. Purely from crypto bookies, I've been enjoying Dexsports.io mainly because they have a lot of prop bets. Rollbit/betfury are also options with a lot of prop bets available. Sportbet.one allows you to bet straight from your wallet if you have an EOS account. Lastly sx.bet is an exchange that also works properly in a decentralized way.

Those are all highest on my list at the moment.