We stayed in Quim's apartment for six nights around Christmas time and enjoyed the place very much. It is comfortable for 6 people, but the third bedroom is rather small, so better for two kids. The beds were comfortable. The place was quiet and very convenient - there's a grocery store two doors down, a subway stop around the corner, and most of the touristy sights are within walking distance of the apartment.
The only downsides were that there were few kitchen accessories and it limited the amount of cooking we could do. The dishwasher was also missing a basket for knives and forks and the oven only had one rack and very few oven-safe dishes. Apart from that, it's a really great place to stay and I would definitely go back.