At this level (64mm flat burr, commercial grinders), I'd suggest skipping new altogether and buying used. The build quality of any of these machines would survive a first or second owner before landing in your hands, and the price for replacement burrs, at least for the SJ, are a pittance compared to the grind and build quality.
If you're bent on buying new, the Ceado is a steal. Manufacturer/distributor support would be a minimal concern as long as the thing ships in good condition.
That said, I'm curious as to why you're limiting the selection in this way. The 64mm flats are great grinders, but for home use, they're overkill.
(I'll ignore the K10 and SJ sitting in my own kitchen... ) Knowing what I know now with the current grinder offerings, I would go with a B-Vario instead of any of the 64mm flats. It's got a similar flavor profile, is more versatile, has a smaller footprint, has multiple distributors and has direct involvement from the manufacturer on several well known forums (CG, HB, etc.) so support isn't an issue.
Good luck on your decision!