It's a bit early to say, but the Tocantins cast seems very likable to me. Got a few 'meh' characters, but the only one I really dislike is Couchebag. I liked the China cast, Micronesia and the Vanuatu cast a lot too.
As for least likable, I'm rewatching Amazon right now and they really weren't as bad as I remembered. I'd go with Fiji, Gabon or Marquesas (though I loved the season) I think. And Cook Islands.
