Let me start by saying the people and Treasure Cay beach was awesome, the facility not so much.
Basically, the resort is tired, it needs a serious upgrade. The rooms are old and dated, and the cable and internet are very poor. Also, the grounds are overgrown and could use some serious trimming.
Now let's get to the food, way, way, way overpriced, and pretty poor quality. $30 for a pizza?!? $20 dollars for wings? oh and don't forget the tax and mandatory 18% tip you have to pay on top of it, to walk up to a counter and get your own food and clean up after yourself. And don't even ask about all the flies
So let's get back to some positive information. As I said, the beach is awesome, as soon as you get in the water, fish come right up to you. The on-site boat rental is great, get a guide, it's totally worth the money. David in the dive shop is a great resource and offers fantastic excursions. Treasure Sand Beach Club, go for dinner, the best meal we had all week. Green Turtle Club and Turtle Cay, take the ferry, great afternoon trip. Oh and lunch at the club is half of the resort, how can that be?
Depending on your length of stay, a rental car might be worth it, we stayed for 5 days, the car was just a bit more than the roundtrip taxi and gave us the freedom to explore.
So in closing, would I go back to Treasure Cay, yes, but I would rent a condo, which are plentiful, and just cook at home, or eat at the Sands club every meal.