Pinnacle would be my top choice. Best book out there IMO. I'm partial to reduced vig, so IIS would also be a high choice. I'd put Hollywood up there as well, though I've been annoyed of late by how slow they've been to post football lines. Plus, through Thursday (I wasn't around to check Friday), they were the only book of mine (out of 10) to not post NFL 2nd half lines. I imagine they'll improve by the regular season as they were fine during basketball. Canbet is also reduced vig but will lower limits if they don't like the way you bet.
Of the non-reduced vig books, I'd put Olympic first. They're often the first to post lines, offer a big selection of lines, and are one of the few books with a window of time for bet confirmation without fear of a line change. If they offered reduced vig, they'd be on par with Pinnacle IMO. 5Dimes is also known for offering a big selection of lines.