You can do both on Saba, liveaboard diving and take a scary Otter plane ride - that's what we did. We spent a few days on St. Martin and then got on the Explorer. The deep water crossing was rough and I got very seasick. I enjoyed the shore trip on St. Kitts but I can't say much about the diving because the vis was very bad and we didn't spend much time there. But I very much liked the seamount diving around Saba from the liveaboard, it was a great trip, and it included a shore trip to Saba.
When they were ready to return to St. Martin we got off the boat and spent a few days on Saba and we flew back; so we didn't land on Saba but we took off and it was an exhilerating experience. The runway is very short and the Otter just revs up and races straight toward the sea.
Saba was an interesting place, the island is just about vertical and driving the road is even scarier than the plane ride. When people give you directions they actually say things like "when you can smell your brakes you are almost there!" (I'm not kidding). You are always walking uphill or downhill, there is little level space and not much beach.
It is a very pretty island and it is topped by a rain forest. All the houses are white, red, and green and all the gardens have flowers. There is very little land available so everyone buries their deceased family members in masoleums in the back yard.
There is little fresh water so you are mostly drinking cistern water and they put guppies in the cisterns to control the mosquitos - so you are drinking filtered (hopefully!) guppy water.
Saba is very pretty and interesting and I am glad I've had a chance to visit it, but I didn't like all the bugs and vermin. I realize it is the tropics but there was more wildlife than I care for. When we were there we couldn't get an air-conditioned hotel room, so we were sleeping under a mosquito net in the heat listening to an incredible racket caused by all the insects. The islanders call them crickets and talk about the "cricket serenade" but they are giant, flying cockroaches that are bigger than the (noisy) tree frogs. And the centipedes are the size of something out of a horror movie! And there were rats scurrying around and bats swooping by, too.
The other day my husband killed a roach on Grand Cayman and he commented "well, at least it wasn't Saba-sized!"
Saba offered more nature than I cared to experience but I am a wimp and it was about a decade ago so things may have changed. If I were to go back to Saba it would probably be on a liveaboard and I would only stay on shore if I could get an air-conditioned room so I could shut the doors and windows tight!
And if internet connections and good communications are important to you then you might find Saba a challenge, but I am just guessing, it's just so small and remote.
We took an Otter plane trip to Little Cayman this morning and that was fun!
