We stayed at Alfama Blue House over the new year's eve, and it was just lovely. The flat was spotlessly clean, has a serene river view with lots of sunlight into the living room. It's super close to the tram, attractions like Castelo, flea market, and only eleven minute walk away from the metro station. It's also walkable to Baixa/Chiado area. Hugo picked us up from the airport and showed us the spot where we could see the view of sun-down Alfama.
There was a couple of things to know, the power might go out if you use more than two machines(oven, microwave, space heater or washing machine) at once. You can turn it back on in the fuse box in the living room. It's an neighborhood with old buildings and renovations going on so there is a chance you might some banging noise in the morning. I slept through as the bedroom is away from the windows but if you are sensitive, earplugs are good item to have.
I'd recommend to friends and definitely come back to Alfama blue house on my next trip to Lisbon.