I saw a review on Backpacking Light's website that indicates that it's possible (and maybe not all that hard) to create an "irreversible airlock" when trying to backflush the filter. By itself, that would be a minor annoyance. However, the poster said that he was told by his outfitter that the airlock ruins the element, requiring replacement (and that MSR is replacing elements damaged this way free of charge.)

Offhand, that seems like a pretty obvious flaw that preliminary testing would have quickly turned up. Jason: care to bust this myth, or confirm it with additional information? (I was almost persuaded to go ahead and replace my problem-free Miniworks, but now I'll wait until I see what's going on.)

Here's the link to the review:

http://www.backpackinglight.com/cgi-bin/...thread_id=13957

In all fairness, the other review on the website said the Hyperflow was a great filter.