We were four adults sharing the apartment - and it was spacious and comfortable. The location was excellent, within short walking distance of mall, plus shops, restaurants - and short walk to bus pickup for Galway City day tours and for ride to ferry (if you plan to visit Aran Islands). We didn't need a car.
Note that there are a LOT of stairs, so consider this if anyone in your party has mobility issues. There's a flight of stairs to reach the entrance, another flight to reach the living/dining/kitchen (and one bedroom) area, and then another flight of stairs to reach both bathrooms and two other bedrooms.
The bathrooms would benefit from some shelving and towel racks and the bedrooms could use nightstands on both sides of the beds.
The kitchen was well-appointed and had sufficient dishes, drinking glasses, flatware - and lots of spices, some coffee and tea. We appreciated having a good sized refrigerator.
All in all, a very pleasing and comfortable stay - we would rent again.