Mediocre at best.
I was in San Diego for two weeks for work, and stayed here the entire time. I would not go back. Its location was extremely convenient for getting around the city. However, the hotel itself was in pretty poor shape. My carpet was stained in multiple places and was sticky with what I hope was Scotch-guard. The elevators frequently took several minutes to make it to the bottom floor; on multiple occasions, I overheard other guests expressing concerns to the front desk staff that the elevators were broken, but no steps were taken to remedy the situation. The parking lot was gated for reasons I couldn't understand; there was nothing really to walk to that might prompt those who weren't guests to park here. The gates were open half of the time, and when they were closed, I did not see one person successfully swipe through with their room key; the front desk had to be paged for assistance every time you wanted to park here. The gym didn't have any sprays to clean the equipment, and the sanitizing wipes they'd provided ran out the first week I was there and were never replaced, making me a little reluctant to use the machinery. 
This is the first Sheraton I've ever stayed at, and it was not a good recommendation for the chain as a whole. Overall, it wasn't horrible, and after two weeks, I'm sure I could have come up with flaws for any hotel, no matter how great. But I would only consider staying here again if there was no other safe and clean option.