The island is amazing. It's not commercialized, all in walking distance, and not "island prices". There was no short on happy staff and there were relatively no waits at restaurants. The beach is beautiful, clean and not overcrowded. Would 100% recommend a trip to St. George's Island.
The house is dated and could use a facelift, but it did not take away from the trip at all. It is much closer to the beach than the pictures give justice. And you cannot beat the views from the back porches. We had three kids and four adults and the size was great for us.
I would recommend bringing extra towels and laundry detergent as the ability to hang towels (beach or shower) and bathing suits is very limited. The queen beds are very, very small queens, if not even full size/double beds.
The rental credit was great - we got bikes and extra chairs. The kids loved the ability to go anywhere on the island with the bikes.