We stayed for 2 weeks with 2 adults and 2 teenage children. The location was amazing!
It was perfect for us and we loved being on the island. If we were to go back to Paris, we would definitely stay on this island again. Although it still attracts a lot of tourists and there are many people in the neighborhood, it seems more peaceful compared to other parts of the city and you did not have the street noise of so many cars and sirens. But, this is still the city, so there were a few nights when there was a bit of street noise from people. You will find a small "express" grocery store and a pharmacy down the street, and 2 smaller stores with mostly produce and a few other items. If you want a larger grocery, the Fan Prix is just across the bridge, a 10 minute walk. The neighborhood is filled with ice cream shops, bistros/brasseries, an Italian restaurant, boulangeries/patisseries, and some clothing and other shops. We enjoyed walking home across the bridge every night, crossing the Seine and enjoying the local musician, artist or poet. Very convenient walk to Latin Quarter or Marais districts.
The apartment itself is a 4th floor walk-up in an old building, with a small elevator. The shower and toilet are in one bathroom, attached to the main bedroom. It worked out fine. Enough storage on shelves to keep items. But if you plan on using the shower across from the second bedroom with the bunk beds, please know that the shower is in the same room, close to the toilet and sink, so the floor and even toilet get wet after showering. So my children ended up using our toilet often, due to the wetness.
There were plenty of towels and linens, but only a minimum amount of toilet paper, shampoo and body soap, so we needed to make a trip to the store down the street on the first night.
The temperature was very comfortable for most of our stay, but when it started to get hotter, around 26-30 celsius, it was definitely hot at night without air conditioning. But I know that many places in Paris do not have air conditioning.