I enjoyed staying in a different part of Paris. The easiest way to get to/from Charles de Gaulle airport is to stay on RER B until Cite Universitaire, and then take the tram to Brancion. This avoids all the stairs at Gare Montparnasse. Going to the airport, you need to buy a tram ticket at Brancion and then get your RER ticket at Cite, so slightly more expensive. Tiny rooms and the world's tinest elevator. Rooms were clean but table wasn't wiped. Friendly staff.
The staff were helpful and friendly but gave some mis-information about where to find a bank/change money. The breakfast was excellent. The atmosphere was more on the party side; I think younger travellers would probably enjoy it more.
The location is wonderful. The 8-bed dorm was huge and clean, but the wifi did not work on the 3rd floor. However, there were computers to use on the second floor. One bathroom for 8 people, with the toilet and shower in the same room, is a bit difficult. Good lockers, elevator. I would stay here again.
I had a private room for my daughter and myself and it was just like staying in a hotel for a much cheaper price. The restaurant/bar was loud inside and it was difficult to get service but the food was good. The swimming pool was cold and the sauna too lukewarm to use. However the staff were very friendly and helpful. The instructions on how to get there leave out the crucial information to turn to the right after the tunnel to get to the main entrance. I would definitely stay here again.
Excellent location right by a metro station in the heart of Montmartre. Friendly staff, clean room, delicious breakfast. Teeny elevator so you don't have to lug your pack/suitcase on the narrow circular staircase. Downsides: tiny room, no lockers, bunks a bit shaky, not much security for left luggage. Paris is expensive, so I think this is great for the money and would stay there again.