I use only the North America island. I would rather be talking and interacting with others that most likely know English well, compared to the worldwide island where it can be frustrating to communicate with someone on the other side of the world.
I only use my country's. I'm always scared that if I go to the international one, I'll meet someone who doesn't speak English and I may accidentally upset them somehow.
I use the North America island when I'm island-hopping only to shop, since it connects faster. Otherwise, I prefer international waters. The potential variety of people you can meet usually makes things more interesting.
I only tried using Club Tortimer once and chose my own country (UK for me). I arrived on an empty island and no one else showed up for the ~10 minutes I was there. I'll probably try the whole world island later, and hopefully have better success of finding someone there.
Whenever I choose worldwide, 9/10 times it's a Japanese player that doesn't speak English. I'll choose it if I'm trying to avoid running into certain people on the regional island. I go to the regional island so much that I pretty much know everyone there. Mostly kids, but they're fun to mess with.
the whole world because i purposefully don't want to stumble upon people i can understand. it's too stressful to discern who is friend or foe when i go my country.
I like the whole world. All the Japanese players I've met there have been nice and we communicate through emotions and go on island tours. I've also met French people but that's pretty much it. It's only annoying when someone comes on, realizes we don't speak the same language and flips the switch. If they want to go, they should just leave not flip the switch -_-
Whenever I go on the North American island I tend to only meet annoying people
I go worldwide because I get less people trying to say hi to me, I'm only there to check the items. There is also in my experience less people who switch flip when they see you are trying to buy an item in international.