I have always enjoyed the spa at GF a LOT. It's great especially if you are staying at the Poly of GF and can just walk over. If not and if you have a car or take a cab, you can park/get dropped off right outside the spa. Tell the driver you're going to the GF Wedding Pavillion - it shares the parking lot.
There are some really good massage therapists there as well as aestheticians. The spa has had some upgrades withing the past couple of years. It is very expensive, yes, but it is nice and if you see to it that you are not rushed, you will have a wonderful time!