We loved staying there!
In the center of Porto old town, almost all big sights are within 15 mins walking distance. The big train station Sao Bento is around the corner, you can also find taxis there around the clock apparently (didn't try at night). There's a bus around the corner that takes you to the beach.
Keep in mind that it is on a very touristy area, so there is always some noise coming in - we just closed the windows at night and it was okay. Since there are a lot of cobblestone streets, ear-plugs are advisable in Portugal in general, I'd say (but we didn't use them here).
The room was spacious, very clean and had enough storage space for our luggage. Towels, soap and hairdryer were provided. We felt like in a hotel. Check-in was super easy, they send you a code for the door-locks on the day of your arrival and that's it.
We traveled as a couple on medium budget.
Definitely recommend this place.