I generally don't buy duplicates for storage reasons. Unless there is something really special to about the packaging design, I prefer loose, second-hand ponies. I did buy one 35th Anniversary Cotton Candy - mostly for contrast with my original flatfoot, to mark the anniversary, and because I oddly found her in the French Canadian packaging at a local toy shop. I'm keeping her MIB for display reasons, it's easy to stand something else on top of her!
Although I like the idea of the scented ponies, I realize that they can't possibly smell like the original ones did, Therefore I can't imagine myself buying any of the others. I think it would take something like Oakley (who I think is v cool and hft , but not worth the price right now) for me to buy another BF re-release.