We stayed here as a group of nine (two families) for a sight seeing weekend.
The flat was in a fantastic location, not far from an underground station and walking distance to many sights. There is a supermarket nearby (5 minute walk) and plenty of places to eat and drink.
Eugen's communication was excellent throughout and he sorted out any problems promptly.
As the flat is centrally located, it was a little noisy at night. The floors were also a little dirty.
Please note that if you are using all four bedrooms there is no lounge. The kitchen is also a little cramped if you want to cook for a big group.
All in all a pleasant stay in a good location.