The apartment is well located, a short walk from the Cretaz chairlift and the main street of shops and restaurants. We were a group of 4 adults and 4 children (aged 8 to 11), and I would say it was cosy but perfectly adequate. I don't think I'd recommend it for 2 families with older children, but for us it worked well.
Parking was easy, with one space in the garage and lots of free parking outside.
Whilst the communal areas of the apartment block are dated, the apartment itself was exactly as seen in the photos, was clean on arrival, and generally well equipped. Some of the kitchen utensils could do with replacement (broken handle on the cheese parer, bottle opener) but everything we needed was there.
One thing to note - if you plan to cook for yourselves rather than eat out, I would recommend stocking up in one of the big supermarkets in Aosta. The small supermarket in resort is fairly limited, and can be extremely busy.
In summary, the apartment suited our needs perfectly. It's not luxurious, but it's clean and functional. Martijn was communicative and helpful, and a pleasure to deal with.