The apartment is nice and big. We were only 4 people, but I would say it's suitable for up to 6 people. The rooms are large, with big windows and comfortable beds. It was great that each bedroom had it's own bathroom.
It's very close to the city center and to the main tourist attractions. There is only a walking distance to the main sights; you can reach The Old Town within 10-15 min.
Over all, we liked the apartment, but there were some things which would have made our stay even more pleasant: some amenities (like soap). Also, the check-in process was a bit of a hassle for us. Since the check-in can only be done after 16:00, we went for lunch upon landing. After lunch we walked to the one of luggage storage places we were recommended. However, when we arrived at the address we discovered it was closed. This was not the host's fault, but it was not pleasant, especially since it was snowing. As we couldn’t walk around with our trolleys and the other luggage storage place was not that close, we decided to wait for the check-in at a nearby coffee house. We then had to walk back to pick up the key at the indicated address and then walk to the apartment. There is only a 10 minute walk between the pick-up place and the apartment, and had it been summer or had we not have bags with us, I wouldn’t even mention it. But, for us the entire experience was not pleasant.