We had a good stay at Raffaele's place, it is spacious and comfortable. Yes, it is in a cellar - which might put some people off - but the great advantage is that this makes the place very quiet and delightfully cool. Even on 10 June we did not need air conditioning. Raffaelle is an excellent host - we had an issue with the shower and he sent people round to hep within 20 minutes.
From the apartment it is a 10/15 minute easy stroll into the city centre. It is an an area with many old buildings and has a life of its own, away from the city centre. There are many local shops and excellent restaurants within a few hundred metres. It's a great place to stay.
The only drawback is that the kitchen is a bit basic - but you are going to eat out in Bologna anyway!