The appartment is just perfect for Athens if you stay there even for almost a week. Even if we didn't meet with Petros and Falia, but they managed our late check-in with their friend (big thanks to Maria).
The appartment is very close to metro station and tourist attractions (but still it's very quiet in the streets). It's perfect for 2-3 people.
Thank you very much for all advises and great stay! Will recommend my friends :)