I will just say that even if the weight [of the Katadyn Hiker] is 13 oz., the HyperFlow is 5.5 oz. lighter. For the lightweight zealots, saving almost 6 oz on one piece of gear is significant.
<img src="/forums/images/graemlins/confused.gif" alt="" /> As you know (since you just said so last week), the 7.5 ounce figure for the Hyperflow is only for the filter itself, not for some of the essential things you would need to operate it in the field.
Fresh off my scale: the Hiker filter cartridge, filter body, two hoses, prefilter, and fitting for Nalgene/MSR openings weighs 349 grams or 12.3 ounces. If the required stuff for the Hyperflow is indeed around 11 ounces or even less, then that's certainly lighter, perhaps significantly so. But it isn't six ounces. Apples to apples, please.