The location is excellent, in the middle of Bario Alto, one of the most active neighborhoods in Lisbon. There are many nice bars and restaurants within walking distance. Major Metro station is also within walking distance.
The master bedroom is well situated and protected enough from outside noises (you still need to close the inside doors for that).
AirCo in all the main rooms lets you survive the hot weather when needed (still I discovered that Lisbon is very "fresh", thanks to fresh winds coming from the river)
Internet bandwidth could be enhanced to provide better connectivity speed. Possible to do remote work from there but you will have to limit video conf calls to only sound.
I did spend 3 weeks there without any problems.
Advice: Don't forget you're in the middle of Bario Alto, a very animated neighborhood, so people living on the other floors (1st/3rd) might be a little bit noisy, but just go talk to them kindly, any problem will then get solved very easily.
In short, highly recommended.
Enjoy it.