Great little flat in a quieter part of town, near Christiania, a canal, small supermarket, some great breakfast spots. We loved it.
Others have mentioned the climb to the top floor, so probably not a place for huge suitcases.
Also note that the child's bed is on the smaller side -- what we in the States would call a 'toddler bed'. Our 10-y.o. son fit in it, but it was a little snug. Not a big deal.
Communication was great. They left a key for us in a shop around the corner, which we found without a problem. We used the kitchen to cook some pasta in the evenings and saved our food budget for the lovely coffees and pastry.
This is a 'real' home, not a permanent rental property. Owners' food in the fridge, clothes in the closet, toys in the child's room. We really appreciated that and felt connected to the place a little more than we have in most other Airbnbs.