Diego was a fantastic host. He always responded within minutes to my messages before we arrived and checked in a couple times during our short stay to make sure we had everything we needed. His apartment was very clean and comfortable, and fairly close to everything. We could easily get to Piazza del Nettuno and other cool parts of the city by foot in 15-20 min. To get into the apartment for the first time, you need to use a virtual key through your phone. Diego provides the link but you'll need internet to access it when you arrive, so let him know ahead of time if you won't be able to connect because I believe he offers an alternative. Once you get in, the physical key is in the apartment and you can use that for the rest of the stay. This is really the only problem I can see other guests having. Overall I highly recommend Diego's place for people visiting Bologna for the first time.