I also stayed at that hotel in early May and found the view of the ballpark to be very unusual. Being in the heart of the Gaslamp District is also a big plus as there are so many great places to eat such as the Royal Thai on 5th - only a few short blocks away. I have eaten there many times and also find the food to be exceptional. I have also stayed at the Marina Towers many times and love that hotel - but it is much bigger and caters more to crowds from the convention center. They do have an amazing pool, however. The only shortcoming of the Marriott Gaslamp, I think, is that the executive Lounge is very small and not relaxing - plus you have to pay for your drinks.
Enjoy - a good hotel with a great location - at the right price.