Stayed at Westin and W.
Westin is better located than W.
Westin did some renovations recently and has a separate elite check-in queue. Their concierge was helpful and staff all around great. The Westin suites have stunning views.
W has the younger vibe and nice bar and open lobby, but the rooms left much to be desired. Even the Extreme WoW Suite had a tiny shower head attached to the wall at a lower than average height (no overhead) and no towel hooks. The service was poor too.
I would recommend avoiding the W, unless that is your vibe.
Status: Ambassador