This place is a gem. It's our third year in a row having an extended stay here, and we definitely hope it won't be our last. We are a family of 5, including two young children (~6 and ~4 yo). Arriving at the house this year, the kids' faces lit up and they proclaimed "Oh yeah! We *love* this place!" And the adults totally agreed.
The location is fantastic: watching the tides come in over the salt marsh from the back deck is unbelievable, especially at sunrise or sunset. The land slips underwater, and the waterline gets ~6x closer -- suddenly it's a waterfront property! We also love walking down to the beach or adventuring across the island to the bridge. At low tide, the beach is wide and sandy, perfect for sand castles, flying kites, collecting rocks and shells, watching the small ocean birds dance in the surf, the teeny tiny crabs scurry, and the snails do their snail-y things, all on a quiet, secluded beach -- it was perfect.
Note that you'll need to plan around the tides, as there is only one way on/off the island, and it is inaccessible if the tide is higher than 10', which typically twice each day and can last for up to a few hours. This has never been a problem for us, but does imply a little planning ahead sometimes.
The house itself is also great -- everything we needed for our family. The full kitchen is really nice for meals on the island while waiting out the tide (though you're also quite close to great eateries like PB Boulangerie and Van Rensellaers's). We had a couple cool, rainy days, and even with 5 of us, we were quite comfortable. On warm days, breakfast on the porch is divine.
Overall, a fantastic place. We're already looking forward to our next trip!