First and foremost, I simply couldn't rate this apartment highly enough. It has absolutely everything you might want.
The apartment itself is clean, well appointed and spacious. We were an all male party of 5; there was plenty of room for us all to have our own space, and with 2 bathrooms and 2 kitchens (not that we really used those), it was just so easy for us all to do as we pleased, no queueing for the bathroom etc.
The location is equally superb. Right next to the metro, but also just a 15 minute leisurely walk to "the" bridge and onwards into the historical part of town or down to the riverside. There is also a lovely bakery right underneath the apartment, and a superb café a minute away with a varied menu and great value for money.
Mario was really helpful on arrival, accessible throughout our stay and went above and beyond when one of our party fell ill and was unable to travel.
All in all there is nothing to find to criticise at all about the apartment, and I would recommend it to all except the infirm or immobile, due to the three flights of stairs needed to reach the entrance.