Just got back a couple days ago from a week long trip to the Turks and Caicos. It was my first time there, and I *cannot wait* to go back. We stayed at the Sands, which was lovely - we had a 1 bedroom oceanfront suite which was somewhere in the range of $300-400 /night - not out of line with similar resorts on the island, from what I'm told. The beach is beautiful, although that's true at all of the resorts, I'm sure. The restaurant at the Sands, Hemingway's, was good but nothing spectacular. I found out very quickly that the drink prices at many of the restaurants are a bit shocking ($7 for a beer, etc.) Anyway, overall we were happy with the Sands and would probably stay there again, although would certainly investigate other options as well to see who was offering the best deals at the time. From talking to many of the other divers and to other folks at some of the restaurants, I heard good things about pretty much all the major resorts on the island, so it probably comes down to what you are specifically looking for in terms of price and so forth.
We dove four days with Caicos Adventures, and I cannot say enough good things about them; they were AWESOME. The boat was spotlessly clean (they even clean the head twice during each trip while everyone is diving.) From the moment we stepped on board we didn't have to touch our equipment; they set everything up for us, changed tanks between dives and rinsed gear (including our wetsuits) each night so we didn't have to lift a finger. You are free to dive your own profile if you want, or they put you with a dive guide, which I recommend unless you've been there yourself multiple times - they always seemed to find things that the rest of us may have missed, even the experienced divers. Our dives were off French Cay and West Caicos - I'm too lazy to list everything we saw, but if you read Tim Ingersoll's trip report you'll get the idea (our first two days diving were the last two he was there, I believe.) On our last day I got to swim within arm's reach of a 6-7' reef shark for several minutes - what a thrill. Fifi's crew on the Caicos Cat - Asa, Kinard, Oliver, Vince and Richard - were super helpful and alot of fun to hang out with; they truly went out of there way to make sure everyone had exactly what they needed and they treated everyone like family. My dive buddy, who normally gets violently seasick on EVERY boat trip here in Southern California, found her seasickness to be minimal even on the two days when it was extremely choppy on the surface.
I haven't tried any of the other dive operators on Provo, so I have nothing to compare CA with, but as I said I would recommend them HIGHLY and will absolutely dive with them on my next trip. I hope you enjoy your trip as much as we did.