Overall this was a great stay and I would definitely recommend Mario's place to a friend.
I took off stars for two reasons:
1) (-0.5 star) Mario and team did a phenomenal job of marketing/selling this Airbnb but in my experienced opinion with Airbnb it was oversold. I usually appreciate honesty and lets face it, Airbnb is much better than hotels 9/10 for price and quality and it's okay if a location has some shortcomings, I'll still be in favor of it. Especially if there are other incentives like great location or history of the site, as in Mario's case. Specifically the area appeared to be much nicer than in photos (for those of you not comfortable with homeless people, not that we had any bad experiences) and the space itself was tighter than initially perceived.
2) (-1.5 star) The bedding quality was poor, much below average than any other place I've been. To be honest, if there is one thing that should be taken care of and prioritized as the hosts investment into their property, it's the quality of ones sleep. A great kitchen and backyard (as in Mario's case) does not make up for it. Specifically, some of the beds had almost no cushioning, as in you could feel the springs/wires in the mattress. The pillows were thin, especially for side-sleepers, so I had to use two, plus a third for my knees (for back issues) and if everyone in my group of 5 slept like this we'd have just enough pillows from the whole house. Blankets were thin but I guess it's warm most of the time in San Diego (?). Also, mattresses were pretty small on the bunks for sleeping two people.
All in all, I would still recommend this place to friends. Though I wouldn't test sleeping 16+ people for a whole week, I don't think that would be a comfortable idea (especially with only 2 bathrooms).