I recently got a chance to sample two SPG properties in San Francisco; It was not by choice but I was walked from the Westin St Francis immediately after a flight from London (not quite the welcome I'd hoped for).
Night 1 - Palace Hotel. 2 double bed room. The room seemed to be in pretty poor shape with marks on some furnishings. However, bed was comfortable and bathroom not too bad (not what you'd expect from a Luxury Collection hotel though). Internet was unusable (0.85 down and 0.01 up) - glad I didn't have to pay the $15 fee. Forgetting the room, I very much liked the rest of the hotel (bar, service, pool, etc)
Night 2 - Westin St Francis - View Tower Room (booked non-view Tower Room). Recently refurbished to a very high standard. Much more impressive than the Palace and comparable with my preferred SF hotel (Intercontinental). I was provided an apology gift (wine/fruit) which was very much appreciated. Again, good facilities in hotel (particularly liked breakfast). Staff seemed to be either excellent or poor - I've had to chase for refund of first night deposit (finally received on my card today despite the stay being on 17/18 July) but front desk staff seemed to handle the walk pretty well.
Despite the problem, I would probably consider the St Francis again as long as I had a similar room.