These movies are really not similar or related in any way, except that I watched them both this past weekend. Oh, and that they're both based on books.
The Fantastic Mr. Fox is a Wes Anderson Movie (Royal Tenenbaums, Darjeeling Limited, etc.), and I usually really love his movies, so I thought I'd watch this one. And I liked this one too. It's just a good mix of funny and quirky and visually interesting. The whole movie is stop action. It roughly follows the Roald Dahl book by the same name (though I never read that book). It's about a fox that decides to steal from some farmers and they try to track him down, and all sort of mischief ensues as he tries to evade them. Fun but quirky is probably the best description. I'd recommend it.
Love in the Time of Cholera is based on a book by Gabriel Garcia Marquez, who is a wonderful writer. (He also wrote One Hundred Years of Solitude - great book!) His books often have a mix of reality-based character-driven story as well as fantasy or myth. Love in the Time of Cholera is about a man who falls in love with a girl at first sight and decides that he will marry her, and essentially waits his whole life for her to be available. He pledges fidelity to the woman, but he can't quite manage it, so he keeps a log of all the women he sleeps with while waiting for her, and it goes into the hundreds. The story is a bit odd, the characters are sometimes sympathetic, sometimes not, but it's interesting. Anyway, I read the book and enjoyed it and thought I'd check out the movie. As always, the movie was not as good as the book. Not sure if I'd recommend the movie or not, but I would recommend the book.