I've never seen, much less tried to use Kryoflux. On the good side, it is a rather new product which means everyone are excited about it and support should be good. On the other hand, Catweasel has been around for much longer so in case you find useful software, chances are most bugs have been worked out. I know software support for Catweasel was improved the other year, shortly after I sold my unit. Possibly though Kryoflux has newer hardware and higher resolution in sampling the disks, so in the long run it would be able to do more.
I would begin with researching which or if both products today readily handle reading and writing Amiga floppy disks. Are there any limitations to operating system, floppy drive hardware, phase of moon? What is "best" often depends on your application. In your case, you have pretty much defined your primary need and can work from there.
I don't know what the Amiga market looks like over there, but is it out of the question to find a cheap Amiga 600? It would have a PCMCIA slot that can take a CF adapter to transfer software from your PC. Then you could write Amiga disks on the Amiga to be used in whichever Amiga 500 you otherwise would play on. Of course that kind of solution wouldn't help you if you get additional foreign formats to handle, so perhaps you're onto the right track after all.