Disappointing - poor customer service; bad location
My wife and I stayed here for 1 week. We had read the reviews and without knowing a lot about San Diego we mistakenly booked the Sheraton Marina. To be fair, there were some good points but overshadowed by some very obvious bad points. The Bad: 1. Customer service - The hotel is not very concerned about ensuring a pleasurable experience. We asked for a decent room since we would be there 1 week. Despite our request we were given a terrible room on the fourth floor with absolutely no view. When we complained, all we received was a lack-luster apology. This lack of customer service reflects poorly on Sheraton's reputation and I will opt for other hotels in the future. 2. Concierge - On our first day we asked the concierge for information on transportation. His response was dismissive and kept restating that taking a shuttle would get us where we want to be and it was cheaper. His information was incomplete and inaccurate. So we waited for a shuttle for 45 mins and eventually gave up after a bell hop advised a cab would be only slightly more money. We later learned the Sheraton is not renewing their contract with the concierge service. Again, Sheraton only offered a weak apology for the poor concierge service. 3. Location - Don't be confused like we were, this is an AIRPORT HOTEL. It is far from all the main attractions and it took us on average 1 to 2 hours a day getting to and from the hotel. It was also very expensive traveling to attractions and the options offered at the Hotel were not economical. Had we known, we would not have stayed at this hotel and we would have paid more for a hotel closer to downtown since the cost of taxis quickly makes up for the cheaper price. 
The Good: 1. The gym was fantastic and people would use it. 2. The pool was very good and the grounds were nice. 3. The restaurants were fair to good. But remember, there is nothing close so you are stuck at the hotel unless you pay $20 each way to go Little Italy for dinner.
Bottom Line: avoid this hotel if you are a tourist. If this is a layover for you or a convention, this would be a good hotel.