Excellent location for exploring San Fran
We stayed at the Club Donatello in June for 3 nights. We were on one of the club levels in a corner suite. We had a fantastic view down towards Union Square. The location of the hotel is great, very convenient to local shopping, restaurants and transport. 
The room was huge and service each day including the turn down service was excellent. I love it when you can tell the housekeeping take great care and thought when servicing your room rather than just refreshing towels and making the bed. 
The gym, spa and communal area on the top level is a great space to relax after a long day. 
The bar on the mezzanine level offered a great selection of drinks and was open late for a night cap drink after a night out.