Matt's place is great, a nice place to retreat to. There are two notable issues I'll bring out first: 1. The home is next to the light rail, you cannot avoid the noise of it going over the tracks. It is literally right outside the window and the clackety-clack goes on through the day and late into the night. 2. The entrance door goes into the bedroom, not the common area.
Having said both of those, I'll give Matt's place 4 solid stars! He is a gracious host with a thoughtful space. The kitchen is appointed nicely, the place clean and well taken care of. The neighborhood is up and coming, so expect some construction noise (right next door as of April 2018) and more just around the corner. Yet the location is so perfect, less than a mile from the Gaslamp Quarter, I could hardly complain.
I got around by uber, bike and foot every day I was there. If I needed to get away from the downtown area, I could. Public transportation gets you to and from the airport in under 30 mins each time I took it, one bus--no transfers (992, get off at Park and Broadway).
I recommend Matt's place and would stay there again. I can sleep through most steady noises, airplanes and trains are fine. NOTE: there are many homeless all throughout downtown San Diego, if you are NOT okay with this or feel unsafe, stay in the suburbs, you will not avoid them in the city. I never had a problem, however.