I switched from Platypus to Evernew several years ago simply because I got tired of losing caps off the Platypus--Evernew caps have a connector holding them to the bladder, so you can't lose them. I can therefore sit here and smugly watch the frantic search for Evernew bladders.
Of course the current popularity in Evernew bladders is because their threads match the Sawyer Squeeze filter, which the newer Platypus do not.
Evernew did have its production severely interrupted by the tsunami two years ago. At some point, though, they will catch up to the demand (especially if Platypus has had sense enough to change back to standard threads) and everyone will be overstocked....
I'll never go back to Platy, though, because I like the Evernew bladders so much better. It's wonderful not to have to worry about losing a cap or mixing up the caps between "dirty" and "clean" bags in a gravity system. With the bright orange caps, the Evernew bladders are easier to find, too.