I stayed in this area during my first trip to SF about six years ago (the Meridien, which was about as close to the Transamerica Building). I found it really well-located for getting to other things. It's close enough to walk to the Ferry Terminal and Embarcadero, and there's transit options to get down to Fisherman's Wharf there if you don't want to walk (it is easily walkable also). Plus close to Chinatown, North Beach, Union Square, Market St., etc. As a big Giants fan, I was also pleased that I could walk to and from AT&T Park, though it's a bit of a trek (I usually stay in Union Square these days). Anyway, SF is a great place to visit and one of my favorites.
If I may, and if you're interested in such a thing, I must recommend taking the Adventure Cat charter boat. It's a catamaran boat that sails from Pier 39 through San Francisco Bay, right past Alcatraz and then to and under the Golden Gate Bridge. It's a fantastic experience with spectacular views of both bridges, Alcatraz, the city skyline and more. And it can also be quite an adventure, as it gets pretty thrilling when there are choppy seas and you could even get a bit wet!