I haven't stayed on land on VG, but the diving in the area is very fine, particularly at the Dogs. You can dive with Kilbride's at the BEYC. But if you're not staying there, you'll have to take the ferry over, or a cab, to make the morning dive. I don't think they stop at other resorts.
I think Dive BVI is now at Leverick Bay, and you can probably arrange with them to pick you up if you stay somewhere else. You'll find some nice beaches in the area, but St. John is the place to go for the finest beaches.
My guess is you get what you pay for, as the Bitter End is at the very top of the scale. There's not much in the BVI's outside of the resort properties. And that's exactly why we love it. We bareboat and dive, and it's very peaceful.
Dee