My main complaint is that the Mini is designed to screw onto the top of the MSR, Reliance and Nalgene bottles. As I had a brought a few off-brand bottles, I found that, in the field, the openings and threads did not match! AS I am unaware of any adapter for the hundreds of knock-off bottles, if you buy the Mini, be certain to take ONLY Nalgene and Reliance bottles with you.
This is why I gave it a 7, the requirement for a specific water bottle when many of us bring the ones we are given as gifts by companies seeking our business.
Last year I purchased the MSR (Mountain Safety Research) Miniworks EX. I'll say right from the beginning that the first one I bought failed on my very first trip resulting in me having to cut my outing short by two days. The pump pivot pin broke and though quite a drag, the good folks at REI replaced it, no questions asked, with a brand new filter unit. They said they'd had two others returned for similar failures. Likely a bad manufacturing run on the pins, things like that happen in production. They made it right. I'm happy. Since then I've used the filter on a number of trips and I feel that I can now offer an honest review of the product.
Read More at my blog: thedamntrueexperiment.blogspot.com