Gabriel was a fantastic host. He couldn't be there to meet me when I showed up, but he still made sure that I had a way to get settled into the apartment. He wrote me a note with a ton of useful information, provided maps and books on the area, and was always willing to provide advice. I was in Sevilla for feria and he even invited me to his caseta, but it just didn't work out with my schedule. The room/bathroom were both very clean, and Gabriel has a kitchen and washing machine, although I didn't use them. The apartment is located a few minutes walk from Santa Justa and is a 10 or so minute walk to Sevilla's historic district.
Overall I would absolutely recommend Gabriel to anyone looking for a place to use to explore Sevilla. The apartment is very centrally located and Gabriel is a great host who makes you feel completely at home.
A couple of reviewers have noted that the apartment is on a busy street and it can get noisy at night. The noise didn't bother me that much, especially after long days of walking around. If you're a very sensitive sleeper, I'd recommend ear plugs.