Has anyone stayed in either of these hotels in Hilton Head? If so, what did you think?

Westin was very nice as of several years ago. Have no idea how well it's been maintained though. It was originally an Intercontinental and we fell in love with it then.

I was in the Westin for there famous seafood buffet. It may not be world reknowned but my family considers it legendary. The hotel looked really pretty and the outside pool area look nice as well.

I stayed at the Crowne Plaza about 3 years ago. The standard rooms are your basic hotel rooms; clean but nothing out of the ordinary.
The lobby area is nice and the pool is nice with lots of walkways, bridges, and vegetation. The concierge was very helpful. The Westin pool area is beautiful. Altough I have not stayed there, it has a stuffier feel to it than the Crowne Plaza. I think you'll find it to be more expensive too.
I definitely would stay at the Crowne Plaza again. Hope this helps.

I agree with Tracy 100%.