The advantages: the terraces. The brightness generally. The generous living/dining + bedroom +bathroom space. Well-intentioned owners. Proximity to la Carboneria and free flamenco watching!
The disadvantages: street noise (cars, 3 cafés right below, midnight guitar players, ambulances because it's on one of the few driveable streets) , kitchen equipped for making breakfast but missing many basics so dine@home possibilities are quite limited ; 1 of us found the mattress fine, 1 of us found it formed trenches that inhibit movement (thick memory foam).
As others have said, there are lots of stairs - 44 steps to the lower level and another 15 to the kitchen and terraces. So, beautiful unobstructed morning light and sunsets but not for those with weak knees.
BTW, the church bell across the street only clangs a few times a day, and at pretty reasonable hours.