I think it's a real close battle between them and Canbet, but Pinnacle is tops. They are fast with the next days lines, their limits are solid, the low juice provides alot of opportunities, they seem to be as solid as they come financially (however I have no way of proving that), I have had really good experiences with the CS department although it has been email only, they offer a decent amount of wagering options and they pay FAST. The bonus isn't world class, but generally the top books don't knock you out with bonus deals anyway. My only complaint is that they don't offer free Neteller on ALL withdrawals, only one a month. Ofcourse they do let you take 8 grand a month for free so basically I don't have much of a complaint.
They are the best out there, that's not to say that there isn't a place in the market for the other powerhouses in the industry; Olympic, Grande, CRIS and WSEX, and more.