The flat is fantastic. It's in a perfect location for touring around Lisbon, just a couple of blocks away from the Metro. I felt very safe and had no problems with noise at all. It's not directly in the middle of the tourist area, but next to two beautiful parks and two art museums. Again, it's on the metro, so it's easy to get around wherever you want in the city.
I will say for the Americans - it is 5 flights of stairs up. Please don't let that dissuade you, but you need to be aware of it.
The kitchen, baths, beds, all were lovely.
(Except the coffee maker. I think I broke the coffee maker, despite having one similar to it in the States. I've offered to replace it - I feel very silly that I couldn't work it properly!)