We had a great experience with Maria Chiara. She wasn't in town when we arrived, so we were received by her mother who lives next door. She was very welcoming and gave us all the information we needed. Maria Chiara was in contact with us permanently, and met us when she was back in Bologna.
The place is great. Extremely clean (obviously cleaned by a professional), and full of little details to make the guests feel comfortable (some breakfast supplies, information about restaurants and landmarks, nicely folded towels...). It is well located (about 150 metres from Piazza maggiore) and perfect for a family of up to four (good sized kitchen and a very nice living room).
I definitely recommend this place (and this host!) to visit Bologna.