Never owned one, as I thought the $30 was way too much for something that seemed useless to me (hey, I was like 8 at the time!). They should've just included it in the system in my opinion.
I had to get it for Majora's Mask...it wasn't an option for me, Zelda fan that I am, not to get it. :lol And then it came in handy for Perfect Dark, as well.
I got mine for free with Donkey Kong 64....although i never really noticed a whole lot of a difference except for some of the games that had to have it.