Positives:
1) Very fast and stable internet
2) Great location - just walking distance to most major points of interest. All needed shops are close by
3) Not bad value for money
4) Fast self check in
Negatives:
1) Extremelly loud. For me it was sometimes impossible to sleep due to all the noise from the street. Construction works, screams, shouts, car alarms, seaguls etc. etc. sometimes all at the same time 24/7 which made sleeping very problematic. I trusted the reviews which said that it's not noisy even though the windows are facing the square, however, from my experience - very loud.
2) The kitchen could be better. Some electronics were difficult to use because power sockets are in very random, not easy to use positions.
3) Very cold, though most old buildings are like this, be prepared. However, a better heater would be nice to have.
4) The mattress is not comfortable.
All in all, I would say it is a good place for a weekend or a week but I wouldn't recommend it for a longer stay.