We just came back from a week at Banyan Bay and loved it. We traveled with two young kids (4 and 8) and it was the perfect place. The beach seems to be one of the nicer ones on AC. The units are very, very well done with lots of room and nice furnishings. The grounds are beautiful and it is just far enough out of town to be quiet but not be that far of a walk. We did rent a golf cart for the week to make it easier to get around with our kids.
Having a full kitchen, living room, etc was key with children. We were able to eat in for breakfast and lunch and go out for dinner.
We found Rico's (the restaurant on-site) to be pricey and good, but not great. We ended up heading into to town most nights, which was fine with us. Our favorite place to eat was Mikey's on the middle street in town.
The pool also was perfect for our kids, with one half being shallow and the other half being deep. The two halves were connected by a little waterfall set up.
We also splurged a got a beachfront unit. The beach was literally five steps from our front door and the breeze of the ocean meant we never had to run the air conditioning.
I agree it depends on what you are looking for. For what we were looking for it was great. In fact it was all so perfect that my wife and I are suffering from a mean case of the post vacation blues.
It was pricey but we found it was well worth it.