My family and I (wife, daughters 11 and 7) stayed here for 4 nights in June and loved it. The house itself has more than we needed. We cooked all four nights, the beds are comfortable, the bathroom is great and it has both a washer and a dryer.
The place is, in my opinion, perfectly located. It is steps away from a fantastic bakery that made all of the Breton treats (and the bread and breakfast treats were also superior). The port is really the best place to be because of the easy parking, the quick access to the old town and the beautiful walking path to Lehon along the Rance. We did the walk twice during our stay. Note that in Lehon along the walk there's a public pool with a water slide. We went and the kids had a great time.
The dedicated parking spot is a must have. We drove to MSM, Saint Malo, Forte La Latte, and Cancale during our 4 days there and it was easy to drive in and out of the location (and parking was never a concern).
The home is ideal for a family with 2 kids travelling with another couple. The home has two levels - the first has the kitchen, a bathroom and a large beautiful room with a queen bed and television, etc. The upper level has an amazing bathroom, a room with a double bed and a room with two twin beds. The 2 floors are relatively separated from one another so that the family and the extra couple would each have privacy.
All in all, one of the best places I've stayed!