All three will likely have similar flavor profiles with similar burrs. (I wish you luck in finding one set of 64 mm burrs that covers Turkish through pour-over well.)

Of the three, the Super Jolly will be the most robust platform. There are doserless mods for it that will improve the workflow. Shop grinders aren't tiny. Check what it might look like on your counter. For me, with enough space for the height of a shop grinder and enough space for a funnel/puffer, I'd go for that. I brushed out a Compak K10 WBC for nearly a decade, so I know what the potential per-shot workflow would be like. I didn't find it terribly onerous on that machine.

The DF64 is, at this time, a pretty well-known quantity. What one "has" to do is sketched out reasonably and doesn't seem onerous or very expensive to me (burr sets aside, but that $200-ish is a constant across all three of your choices).

I can't reasonably comment on the Kopi as it is still pretty rare out there. Some initial thoughts on Kopi Deva single-dose grinder

It seems to me that the development in new burr geometries is strongest in the 64 and 98 mm sizes. It is my guess that there will be a lot of changes in burrs over the next 5-10 years. For me, I'd go with a platform for burrs that is likely to have a range of choices as well as a strong resale market for the burrs that you may not love, but someone else wants and will pay for.

dilin wrote:A used SJ with new burrs or SSP might be the best value here. Although as Jeff said you have to contend with faffing around it for single dosing. Mine has a doser which is beneficial for breaking up clumps.

I add my vote that of the 3 choices the OP listed, the SJ provides the best value (and probably durability). In regard to the benefit of the doser, I used to believe as you do that it effectively breaks up clumps. But based on my experience with both the Mini and SJ pre- and post-conversion to single dosing via DW mods, I believe it is rather ineffective in doing so. I had a great deal of difficulty avoiding uneven and spritz-ridden naked extractions until I did the single dose mods and ground into a dosing cup before pouring the coffee into the PF basket and then performing WDT and wedge distribution plus tamping.

It might just be something about the way the SJ (or the Mini) grinds, but single dosing directly into a PF rather than first into a dosing cup just doesn't cut it with either. I suspect that's true for any horizontally mounted flat burr grinder, but I could be wrong. Folks who use straight thru conical burr grinders have reported good results dosing directly into the PF, but I don't have any experience with conical grinders capable of doing that. My hand grinders and ROK all employ dosing cups.

old_bear wrote:1. All range of roast for espresso (with local roasters crazy about acidity and fruit/berry stuff),
2. Pour over,
3. Turkish grind.

Even number 1 is not really possible with only one grinder in my experience. If you mean that you want to brew dark roasts as well as Nordic roasts to their full potential. You can get 2 out of those 4 priorities in one grinder. I'd suggest to go for a combination, for example that SJ or DF64 with SSP MP/LS burrs for light roast espresso, and then for example a Niche Zero for the darker roast espresso and turkish.

I did prefer single dosing on a Mazzer Major because there was a lot less popcorning compared to the Mini E I'm now using. But there are less burr choices and those burrs are more expensive. 64mm is good value.