I have stayed at both.

The rooms at the Westin are acceptable, but again, no suites. The lounge was OK, food adequate..

I stayed at the Sheraton a few months ago and will again in 2 weeks. The rooms were nice, my hours did not allow for lounge enjoyment but it IS open all day with drinks.

I am leaning toward the Sheraton.

Honestly, they are 50 yards apart, stay at the Sheraton and sample both.