There are two Sheratons. The Libertador is in the old downtown CBD area. It's crowded (careful about pickpockets on the street and especially around Florida) and not especially interesting, but the port and its new art museum, outdoor cafes, restaurants, etc. are close (walking distance), although the area is a touristic. My high floor SPG room was newly renovated, not large, but pleasant enough. The lounge is pretty basic and service can be hit or miss. Expect to wait for a taxi.

The PH is stunning. IIRC P&C rates can be used with Diamond Suite Upgrades. so you could get a wonderful room in an iconic hotel for a quite reasonable rate in cash. It's also in a good neighborhood and within walking distance of some museums, fancy stores, and the famous cemetary. The hotel has some interesting restaurants and bars which of course are not cheap. There are lots of staff, including security people standing around. The indoor pool is small but very nice.

The convention center Sheraton is within walking distance but in a different neighborhhood. It's connected to and shares some facilities with a LC hotel. I haven't stayed here but I have stayed in the other two.