The DF64 has its fans, but it's not a machine I'd personally recommend. That said if you're happy with it, that's wonderful! From what I've experienced, the SSP burr upgrade is arguably needed to get the most out of it (meaning you're in Niche-spending territory) , as well as some 3D-printed accessories to improve the workflow as well as stop coffee grinds covering your work surface every time you use the thing. Even if you stick with stock burrs, I've read you need to go in and manually align them because they're not great out of the box.
End of the day, it's fiddly, workflow is a bit of a pain, and you need to be technically-minded. It's definitely a product that can work really, really well for you, but it has a lot of caveats. The Niche I can recommend without any disclaimers - especially now it has an 83mm flat-burr version.
As for the Eureka Mignon Specialita, I have no experience with it, but sounds like it's a great machine that shouldn't be overlooked!