I recently stayed at Marcella's apartments with 7 friends. Marcella was a helpful and accommodating host - allowing us to check-in early in all 3 apartments we were using and issuing a refund when our numbers were less than expected.
The apartments are spotlessly clean and beautifully decorated, plus the location in the lower town is really central so super convenient for walking around Bergamo or to get to the train station and airport.
We all thoroughly enjoyed our stay!