I just returned from a weekend stay at Green Harbor. A few friends and I had a relaxing getaway there in one of the 3-bedroom cottages. The view from our deck was spectacular and we could have sat out there for hours.
The best things about the resort are the staff, the accomodations, and the "extras". The staff could not have been friendlier or more helpful - from booking, to check-in, to check-out. The cottage was clean and well-appointed. I had thought we were supposed to have a dishwasher, but alas, our cottage did not have one. Not a big deal really. The "extras" in the way of beach chairs, lots of towels, bikes for borrowing, etc. were a plus. They are not stingy here with stuff like that. Plenty of soap, plenty of clean towels, etc. It was nice to not have to request those things like you often have to do at many hotels.
It was a bit pricey, but for what you get, I understand why. I typically prefer the outer cape over this mid-cape location, but I would definitely return to Green Harbor and may also consider bringing my family next year as it is very family-friendly as well.