The Sheraton and Westin are, for all intents and purposes, connected by a large shopping mall. I think historically the Westin WAS the far nicer of the two, but with the substantial renovations at the Sheraton in the past 3 years and the aging decor at the Westin (about to begin remodeling I hear), I've actually decided that the hotels are about even.

The Westin has a slightly better location (but not by much), but the rooms at the Sheraton, in my opinion, are excellent following the remodel.

It's really about a draw. If you can get a great C&P deal at the Sheraton, then go for it.