We had a good stay overall!
Positives included proximity to RER and Metro stations, almost quiet neighbourhood (except when the bin lorry arrives early in the morning!), the amazing Schou boulangerie and patisserie located three blocks from the flat and a fully equipped kitchen, comfortable beds and even a TV.
The only negative was having a little less space for the money we paid but it was 3 of us and the living area+dining+bedroom was a bit too cramped for all of us and the bathroom was tiny but usable. However, the arrangement would work for budget travellers! Also, during peak winter (we were there during Christmas and New Year), the heating is just enough - so make sure you wrap up well inside the flat as well. Shouldn't be a problem in summer!