Water Purification Pump vs. MIOX Purifier

[sanjuanrider]

I'm trying to cut weight and I was given an MSR MIOX Purifier for Christams but have not yet used it in the field.  I have always used a pump and don't mind using it but it is definately twice to 3 times the weight of the Miox.  Does anyone have any experience with using the Miox and good/bad information about it for multi Day trips? When I test it at home on large quantities of water (4L) the test strips always come out negative even though it is very clean tap water (Denver Water).