Both feel extremely business oriented to me. Try to avoid both - for leisure travel at least - if I can.

My last 2 Westin business experiences were in Tampa and Las Vegas.

Tampa: just OK.
Las Vegas: bad.

My two Westin experiences before that - both for leisure - were the complete opposite.

Greenville SC: above average.
Madrid: awesome!!

I tend to avoid Sheratons at all costs. Unless we're talking Portugal or BKK or the like...