Matt's listing was the perfect spot to stay for my work trip! It was very clean, comfortable, and in a great location--only a short walk from the convention center and gaslamp.
While the area is obviously quite loud in the evenings, that isn't any fault of Matt's--just something to be aware of for anyone looking anywhere in this district who tries to go to sleep early. I didn't personally find it to be a problem. Also, as a solo female traveler, I felt very safe staying here, even on evenings where I was walking back somewhat later.
Overall, I enjoyed my stay, and would gladly look at Matt's listing again if I find myself back in San Diego.