I own the mini and have been trying to talk myself into the Amigo gravity filter for sometime.
I have a love/hate relationship with the Katadyn Mini.
It's small, light, eminently field cleanable, seems *very* solid, has very good filtration and is a royal pain in my @** to use. It's *slow* and difficult to pump, even when clean.
The MSR Hyperflow makes me jealous! I would probably buy that, if I buy another pump.
The Nano Technologies pump looks nice, but I urge you to be careful. They state Nano-KDF technology. The only info I can find about this is Chinese. That raises red flags.
I researched this technology in the past, concerning my "Survival Straw". This little filter makes all kinds of claims of filtration effectiveness, including "meets (some nebulous) FDA standards", "Certified", "Destroys Harmful Bacteria and Viruses" and "All Test Certifications Available Upon Request"... guess what? There was nobody to request these certifications from, as the company went out of business (www.usamarketing.com Atlanta GA). I can find out nothing about this thing, so have been afraid to ever use it.
I like the Amigo Pro gravity filter, but it seems too heavy for what it is.
I am very curious about the (hopefully) soon to be released MSR/Platypus in-line filter cartridge. I have suspected that it uses the same technology as the Sawyer, but have no verification of this (except in this thread). I have been on a waiting list for a Platypus Clean Stream replacement cartridge for over a month now
I bought a few parts with a lighter gravity filter project in mind, to test the Platy inline filter, but it has taken so long, that I made this: cheap gravity filter
Hope the Platy/MSR inline filter is lighter.