This was my first experience using airbnb, and overall was a positive one.
In order to be completely honest and fair, I will list pro's & con's:
PRO's: The host has done a great job remodeling the duplex, with brand new, very nice stainless appliances, tile and granite throughout, comfortable beds, washer & dryer, and nice patio furniture. In short, he has put some $$$ into it. The location is within an easy walk to the convention center, Petco Park (where the Padres play), the Gaslamp District, and other nice sites. There is a grocery store about a block away, and plenty of nice restaurants. The wifi network was very adequate (fast).
CON's: While the location was convenient for us (attending a Firefighter's convention), it is on the edge of a downtown city area. Sadly, San Diego has a large homeless population. We came home once to find someone's belongings on the front porch. That was not a big deal to us, but the neighborhood isn't exactly quiet. The lot next door has heavy equipment storage (along with early morning startup)!
While the space was very clean and nicely remodeled, other guests should be aware that this is not 1 large house. It is a duplex, separated by a common wall. Each side has it's own kitchen, 3 bedrooms and 1 bathroom. The front doors are right next to each other. This layout was fine for 5 firefighters attending a convention, but might not be appropriate for a family on vacation. It would be great for a group attending a ballgame, etc. There are no dressers in either unit, and only a few hangers in the closets. Vanity sink areas are very narrow (again, fine for fighters, but maybe not for my wife & 2 daughters)! The nice new TV's do not offer cable, only internet sites, such as Netflix or Amazon (only if you subscribe).
BOTTOM LINE: We had an overall good experience and would not hesitate to book here again, or at one of the host's other properties. We saved about $1500 using airbnb over booking 3 hotel rooms.