My wife and I stayed at the Sherman Shack for a week in July, and we found it a very pleasant and convenient place to stay whilst visiting San Diego.
The accommodation is of a high standard with all you could need (wifi, air con, well equipped kitchen etc), including a BBQ in the garden that we made full use of. It's an ideal spot for a city break, with the Gaslamp Quarter and Downtown only a 5 minute drive, and Balboa Park and Coronado (an excellent beach) only 10 minutes away.
We initially thought the neighbourhood was a little rough, but in reality we never felt unsafe and it's 'scruffy' more than rough.
John was an excellent host, very knowledgable about San Diego, and also very accommodating when we unexpectedly arrived a couple of hours early.
Overall, we thoroughly enjoyed staying here and definitely recommend it to anyone looking for a bolt hole in San Diego.