I was using a book not sponsoring this forum when I first starting betting online but for about the last month I have been using pinnacle sports as they have better juice rates than the other book I was using. Their customer service is very average from my experience but their juice rates are top notch, I'm not sure I would trust them with thousands of dollars but if you're talking 1K or less they got the best juice rates anywhere that I've seen so they're probably worth a look. I've also heard alot of good things about Canbet.
The only sure thing is that there is no sure thing.