Great location, just a few minutes walk gets you to most of the main things we went to Athens for.
Everything was very positive with one minor exception, which is that it was very hot due to no A/C. He does provide a fan, however, but the bed is situated atop a loft, making it pretty hot during the summer. This probably isn’t usually an issue though, we had bad luck that our one day in Athens was 100 degrees Fahrenheit. So as long as you don’t visit on one of the hottest days of the year I highly recommend it.