The balcony overlooking the river is really special. The rest of the apartment was very nice - clean and comfortable. There’s a market on the corner that was very convenient for getting basic supplies for breakfast etc. And did I mention the balcony?
The only other thing I would mention is that there is a fair amount of hill and stair climbing involved. That may be inevitable wherever you go in Lisbon - or at least the old part - but don’t be surprised.