Beautiful hotel, close to Gaslamp, Waterfront and Little Italy!!
We had a lovely stay at the US Grant. Staff were very helpful and nice. The room we stayed in was beautifully decorated, definitely 5 star. The bed was wonderful and bathroom was beautiful, vessel sink, marble, lovely. Robes, slippers, nightly turndown with chocolates. Housekeeping also would stock the ice for you in the evening, so very nice. 
The hotel was very centrally located, close to all the must see areas. The only drawback is being so close to the fire hall and police stations, they are around the corner--sirens went off every night at some point. Not good for light sleepers. It is downtown San Diego so you have to expect some city noises, however this is why I've only rated as very good, rather than excellent. 
It was great to be close to Horton Plaza, Starbucks directly across the street, along with CVS so able to pick up the necessities close by. We walked to Seaport Village, Gaslamp District, Little Italy and Horton Plaza, so great location. We had a great dinner in LIttle Italy at Zia's Bistro, and brunch at Cafe 222, south of Horton's Plaza. Worth the walk to these two places. Also went for dinner at Croce's, live band on Saturday night so was alot of fun.
Valet parking is the only option however at $35 per day so if you have a car, you do need to note this.