Dominica is different. It is a volcanic island, with steep sides that are actually the sides of mountains that drop into abyssal depths within a few miles of shore. There are almost no sandy beaches, and the coral zone is narrow because of the rapid depth drop offs. There are more enormous boulders than coral heads. Unlike many other islands there are no vast shallow reef gardens.
Despite all this, the diving in places is spectacular. Around Scott's Head there is an enormous undersea bowl, formed by an ancient volcanic explosion. The diving there is amazing. The proximity to the open sea brings in all kinds of pelagic species, and the underwater scenery is nothing less than spectacular. There are great areas to dive mid-island, and also in the north.
The water clarity is usually excellent, even after heavy rains. Dominica is mostly rain forest, so it does rain a great deal. Most of the rain is in the interior, though, with clouds forming around the high mountain peaks, silent lightning flashes a few miles away while the sun shines brilliantly. There are hundreds of beautiful warm water rivers flowing freely into the sea. The diversity of sea life is amazing. You can see things there that are seldom if ever encountered elsewhere.
Topside, Dominica is a natural paradise. I have seen the kind of rainforest that covers Dominica only on the South and Central American mainland. Prehistoric giant ferns towering 20 feet high, trees so vast you can't see around them, deep green ground cover softer than a featherbed. The roads are very bad, but I drive there all the time, standard shift 4WD, with no problems other than an occasional detour because of landslides. There are no poisonous animals, and the jungle is unusually gentle, almost enfolding.
Warm microrain too fine to be seen, only lightly felt, while the sun is shining brightly from a cloudless sky crossed by double rainbows can be as addicting as any narcotic. The deep water so close to shore means you can, on rare occasions, see whales while having dinner, both you and they. How the water sparkles as those giant flukes toss fish into the air! Wildlife is everywhere. Not many people, and almost no tourists.
The drinking water is quite safe. There are not too many good restaurants, and the food is only fair in most places. I always rent my own place, and it's possible to get local women to come in and cook excellent local cuisine very reasonably if you buy the essentials. You do need a car. There are a few good restaurants, though. Menus are limited.
I fly Seaborne out of San Juan. It's an excellent airline, much better than LIAT. The flight from SJU to DOM leaves shortly after noon, so unless you can get to San Juan very early an overnight stay is unavoidable. I fly in to SJ at night, overnight at the Airport Hotel, about $130 for a double.
Check Nature Island Destinations for rental details. Colin Lees is the guy I deal with. Rentals are very cheap, but a car is really needed. I would never consider not having my own transportation because of the freedom and ability to see wonderful things.
Dominica is a poor island, but people are friendly and generally polite, and as a rule do not bother you in any way.
I go as often as I can. The diving is wonderful, and the interior is spectacular. No place is perfect. Dominica is not for everyone, and can be physically difficult. I'm in my 70s now, and so far so good. I kind of feel sorry for the tourists who stay at diving dedicated AI, and miss most of what is one of the world's wonders.