I spent a week in Statia in 2000 and enjoyed myself. Its quiet and quaint, smaller than Saba. Its black volcanic sand, with a dormant volcano on one end of the island. Most of the island is walkable but low geared bicycles would be ideal despite its hilly terrain, hills makes for superb views in most lodgings. A Med School was just finished when I left, and the influx of students could have changed the amenities a lot. However, this means Statia has its own hyperbaric chamber.
We dove with Dive Statia. What I didn't like about the dive operations, not just Dive Statia, is they were by the book PADI table dives, thus annoyingly short. Nice reefs, not much life when I was there, am told things are changing. STENAPA reef has a few artificial reefs. Nothing spectacular to write about that you couldn't see elsewhere in the Caribbean, but would do it again because of remoteness, peace and tranquility. BUT ONLY IF:
I could dive my computer not PADI tables
If they rent bicycles
find a shore dive spot to a good reef, there weren't any when I was there
Kings Well was the only hotel in the island, others are B&B or rooms for rent.
Statia had beautiful dark nights, a good telescope would have been helpful. The sky was cut by the milky way, and in the darkness, there were shooting stars every night if you stared into the sky long enough.
I sure hope it hasn't developed too much since then.