We stayed at the apartment with a group of five adults and my nine months old son. The place turned out to be bigger and more open than I expected (also through the large door between the kitchen and living room). An additional advantage for us was that it is very neat, in the sense that not much 'stuff' is standing around that needs to be saved from a toddler. All baby equipment was provided too. Everything else was easy, all we needed available, and shops, bakery, restaurants, play ground and metro close-by! We also made use of the Citybikes next to the metro station (1 Euro to sign up and then it's free to ride for an hour each time). One little issue was that the room with the single beds got a bit of noise from the courtyard during some of the nights.
In summary: We very much recommend this place for a visit to Vienna!