The Chatwal: Used to get to stay here a lot when I worked for a different company. Loved everything about it. The old time music in the bar really was a time machine. Plus, I once got to ride in the elevator from 10 to 1 with Christina Hendricks. http://www.imdb.com/name/nm0376716/
Liberty, Boston: Received the top suite (Ebersol) once. Among my best upgrades ever, and my wife happened to be with me as part of a stay-cation.
Maria Christina: Had a great suite. Really classic.
US Grant: Very cool, great location
Park Tower: Always had a love hate relationship. When I got a nice room and it was ready (love). When they were stingy about upgrades (hate). There are extensive threads about upgrade challenges here. They definitely sell a lot of premium space here outright, but there were a number of situations where front desk staff disclosed that they were limited in what they could provide for upgrades due to house rules. Haven't stayed there in a while, so don't know current policy.
Palace, SF: For a time (maybe still) they were jerks about Plat recognition. As such, I have never returned despite a grand hard product.