I recommend to stay at Silvia's flat. It's clean, stylish and from windows there is a view to the Citta Alta and San Vigilio Hill. Silvia is very friendly and helpful person, and it seems that Bergamo has no secrets for her. In the kitchen there are basic groceries for breakfast, equipment like coffee machine, toaster, oven and microwave. There is a little terrace for those who smoke. Rooms are cleaned every day.
In five minutes of walk there is a main railway station, which is transportation centre where it's possible to take train, light rail, bus to the airport, or to Upper Town (Citta Alta). Anyway to the Upper Town it's nice to walk, it's only 15-20 min by foot :) In five minutes of walk it's district Citta Bassa with a lot of bars, restaurants where you can spend a good time, especially in the evening when it's aperitivo there. Ask Silvia what aperitivo is ;)
Silvia also gave us discount card for a dinner and wine in VOX Lounge Bar & Restaurant. For her guests only :)
I recommend for those who want to stay in Bergamo only, and those who want also to travel around the region from here.