The flat is in a great location and walking distance to the very hip Montmartre area, including Sacre Coeur, the Opera and major department stores (Printemps, Galeries Lafayette). It's also convenient to get to most other parts Paris due to its proximity to the Metro and RER.
The flat itself was clean and as advertised. The furniture was comfortable. I went primarily for business but brought my family along. It works just fine for a business trip. The layout may not suit all families (I went with my wife, and 3 children aged 8, 3 and 6 months). Upon entry to the flat is the reception, which is small and fits a small dining table and sofa. This leads down a hallway to a basic kitchen and a set of narrow stairs up to the bedrooms and bathroom. At the top of the stairs is the first bedroom. You walk through this bedroom to the 2nd bedroom which has the en suite bathroom. It's the stairs that may not suit all families although we made it work just fine. The reception also doesn't allow the space for children to play so we spent most of the time in the bedrooms. The flat is across the street from a theater so you may get a bit of noise but the windows are double pane which keeps it pretty quiet.
Eric the host was great - very friendly and welcoming and made checking in and out very easy.