What a beautiful apartment in a great location. I stayed here for almost a week while attending a conference at convention center, which is walkable from the apartment as much of this area of Gaslamp (public transport very accessible to get elsewhere). Building also has awesome gym, pool, and work facilities--which you also have free access to (and that I wish I knew about before coming!!) This would be a PERFECT place to crash for a weekend getaway to San Diego and partying in Gaslamp. Location is definitely in the *city* with some street people nearby, but the building is very safe and clean with key fob entry and security guard; I would expect nothing else for a centrally-located downtown location in California! Pro tip: Downtown San Diego is known for limited parking, so if you don't want to move your car for several days park in the lot in Gaslamp near the convention center for $20/24 hours.
Host was very flexible and gracious when I was very late for check in, even providing me a few extra clothes hangers since I forgot mine. Apartment was very clean when I arrived, wasn't quite as clean when I left (but I was there for like 4 days). They provide a door lock to your room, and I would recommend just keeping your stuff in there to prevent it getting mixed up if the roommate who shares your bathroom is also there (he often travels, so it's a 50/50 chance). That roommate is messier, sleeps on the couch, and sometimes makes a bit of noise when he comes back later at night. Otherwise it's a pretty calm and quiet apartment [I believe that's what the host will expect you to reciprocate]. Both hosts were very kind people, and very welcoming and friendly. FYI there is also a supercute small dog that the owner has great command of; he'll keep him in his room 100% of the time to avoid disturbing you unless you explicitly let him know you don't mind otherwise!