The Wynn is probably the best technically, but I am more comfortable at the Venetian. I have just been treated nicely there the last two years I went for the Breeders Cup. Also the Asian place right on the corner of the sportsbook is a much better option than the deli appended to the Wynn sportsbook. As an aside, the Venetian poker room has a lot more action than the Wynn.
If you want to play horsey futures, however, you have to visit the Wynn (also any William Hill outlet).
http://www.williamhill.us/racing/fin...ll-race-book-2