The apartment was great! It is in the middle of the old centre and there's a small grocery shop around the corner. Even though the apartment doesn't have any windows (which we already knew before we saw the apartment so we should not complain about that) it is a really cozy (but big) apartment. We were only with the two of us but there's plenty of space for more people.
Riga is a nice city to visit. We met some local people and discovered the city, if you're not meeting any local people: go to the tourist office and there they have maps with recommendations of locals for restaurants, sightseeing, markets and stuff. We used that as well.