The flat is nice and cozy, the location is awesome, the only time we had to take the bus was when visiting Belem, otherwise, we only walked, getting to know the city. The views from the roof window are great, both day and night and had no issues whatsoever with the place.
I would recommend packing light. The flat is on the last floor (4th) of a nice old building, without elevator. But this will also help you in the steep hills of Lisbon :)
Even though we didn't meet Miguel, he was very helpful and provided everything that was needed.