Theo's place is great, is so close to the city center. It's also located on a very quiet street, so you won't be bothered by noisy people.
One very nice thing is that you have a separate entrance.
One thing that it would made us happier was if that the place was cleaned a bit better.
Theo, as a person, is very nice, polite, eager to help or to assist with great informations.
So, visit Athens and book at Theo's place, you won't regret it!