On Batlha square, right next to the Mercure in one of Porto's main squares. The problem is that the once very lively square is no longer so and it is a bit uncomfortable to walk there at times.
Rooms were small and basic. Elevators were very slow and common spaces uninviting.
The team at reception were helpful and nice but there was always a line to wait for them.
No parking is available at the hotel but they have an agreement with a parking lot across the square for a very reasonable daily rate. There is no need for a car inside Porto so in case you arrive with one - park it and forget it until you leave.
Breakfast is served in one of the cellar floors - there is a rush hour everyday and there is not enough staff to clear and clean the tables or fill in the food.
My room had a window as I requested but it opened to a roof with some pipes and the AC compressor. Other parts of the view included some deserted buildings now occupied by pigeons and cats. I did not feel secure in that room.

Good location, clean rooms, helpfull staff and nice breakfast.

Exelent lociation.Liked the balcony looking on the city and the Praça.The staff was very friendly and helpfull.Room was small but not that it was a problem.Breakfast was good but with little variation.It was everyday the same .There was no noise from outside and we could sleep very well.But We had a nice stay and the price was good.I would advise this hotel to others.

Spent 4 nights on a short break with 3 other mature couples recently in this hotel and we were all very impressed. Location is really great; rail, metro very close and the tram and tourist buses stop right outside the hotel. Close to shops and all attractions. We paid 70 euros a night through Booking.com, which was good value. Not true that you get rubbish rooms if you book through a discount site if our experience is anything to go by.
Hotel is very clean, staff are really excellent, they couldn't be more helpful and knowledgeable about the area. We had rooms on the 5th and 6th floors overlooking the Praca - rooms were well-appointed (hairdryer in bathroom, toiletries, tea/coffee making facilities, good hot shower) and we all found the beds very comfortable. Very quiet indeed. Sheets and towels seemed to be changed every day. We requested more pillows and they came straight away.
Breakfast is plentiful and the food is good. The first two days we were there, the hotel was full and breakfast area was very crowded (did run from 6.30 to 10.30 though) though we did manage to get a table both times. Staff a bit rushed off their feet. Next two days, hotel was quieter and it was fine.
Bar area in hotel is very comfortable and prices reasonable. We ate in the cafe/restaurant next door (on right as you look at the hotel) which was nothing to recommend. We only went there because it was raining so hard!!