When we're visiting big cities, we normally prefer to stay at hotels instead of B&B, but this time we have been very happy to have chosen Casa Ferrari.
Ludmil was a wonderful host (so as his daughter Eva), helpful in any way: starting with the parking (our GPS didn't work and he personally accompanied us to the parking place 10 minutes away from the house), going on with history about Bulgaria and the main monuments we visited, following with suggestion about walking tour, taxi to use, restaurants and so on.
We really felt as at home and surely recommend this B&B to whomever will stop in Sofia.
Very clean and soundproof room: during the day you can use the living room and the kitchen (Ludmil don't live there, just come for breakfast and to see that everything is fine).
Bottle of water were kindly offered by Ludmil and available in the big fridge in the kitchen
B&B is close to the pedestrian way (5 minutes by foot) and the touristic city center, in a very safe area.
Very good relation between quality and price.