My equipment right now:
Lelit Bianca
Eureka MCI (Instanteneo) 50mm grinder
Sette 270W

I am probably going to ramble a bit, sorry in advance for that : )

I am thinking that I could get better more consistent results on my beloved Bianca and get there easier with a better grinder than the Eureka MCI. I have come to hate the Sette, it is fuzzy to dial in, the lower ring can turn the upper by accident, the dual ring dial just annoys me, and I have one more than one bean type experienced that I much preferred the taste from the Eureka flat over the conical Sette (Of course I can't be sure it is a flat vs conical issue)

I have pretty much landed on two different beans I like, so won't be switching all the time, and will keep the small Eureka when I get the new one.

My initial thoughts/Choices:
I thought I was a single doser, I modded my MCI to SD, but I have begun thinking that pop corning and diminishing bean pressure resulting in different fineness is maybe not worth the hassle.
I might just go for a hopped up version, then keep 100g in the hopper which I would drink in 3 days, then fill up again from vacuum sealed bags kept in freezer.

Instead of weighing out one dose and jumping through hoops to get it all out via bellows and whistles, just buy a Eureka Atom and time for 17g out and use manual grind mode to top up to 18g - Pros would be constant bean pressure, no fiddling with beans out of a bag, just weighing the porta filter a couple of times

All the SD grinders in my price range come with, it seems, a lot of uncertainty in terms of build QC and clogging issues and regrinding of beans, vibrations and so on....


Are there any flaws in my thinking so far?

If not then which Eureka Atom should I get?

I discounted the Eureka XL because the manual grinding is push to grind push to stop, which would most likely annoy me.
Timed dosing will not be accurate enough to rely on I think? Or is the burr size to burr chamber enough of a win that I should just program one button for very small burst?

Eureka Atom has the right interface for me and I like the look of them

So my thoughts on which one to is as follows:

The Atom 60 is priced perfectly, but I worry that the 60mm burrs leave too much space in the burr chamber, so that a lot of coffee is left. The same with the 65mm version - But the 75 is expensive...
I am also considering if 65 or 75 version is much easier to get good tasting espresso then I should go for them

If had the money easily, I would of course just buy the 75, but i don't so I worry about over spending, if the gains are in the single digit percent, then I can't really defend it to myself...

I have spent so many many hours googling this question, I just need some input to make this decision. Like are my thoughts relevant or what would you get, or what did you get? 60 vs 65 vs 75 in terms of added value vs cost

Please help me make sense of my first world problems : )

Eureka ATOM Specialty 75 GBP 869,-
EUREKA ATOM SPECIALTY 65 GBP 711,-
Eureka Atom 60 GBP 583,-

TL;DR

I want a Eureka Atom model, but do I need to worry about 65/75 burr chamber dead space? I want a good grinder to maximise results from my Bianca, can i get the 65mm version and compensate by cleaning it weekly or is the 75mm so superior that 200GBP price difference is just madness to try save on?

If I was between 65 and 75 and it was 150-200gbp in difference, I would spend the extra and get the 75 and not have to think "what if". But thats just me. Worth considering might be burr options for future upgrades?

Since you single dose, have you considered the Niche Zero? You stated that you don't want to deal with popcorning, however, my understanding is that they now ship with an insert that stops popcorning. I have one on order that I am hoping will ship in February. Any new orders now look as if they will ship in March.

FWIW, I also came from a Sette 270wi. The noise and plastic gearbox issues finally got to me and I sold it. I now have a Eureka Atom 75 (and Ceado E37S) and I'll just say the Atom a delight to use. It's both shockingly quiet and shockingly fast. The grind is excellent. I think there's a slight loss in body compared with the Sette, but there's greater clarity. The flavor is less "muddy" for lack of a better word.

I don't single dose, not sure how it would be for that. But it's a phenomenal hopper grinder. Not much retention, I don't even bother to purge a gram or two for the first shot if the day anymore.

I recommend the Eureka Atom 75. First real espresso grinder I've had and I won't need to upgrade for a long time. First off it's available- in 4 different finishes. I have the stainless and it's elegant. Very quiet, can grind 18g. Beans in 3 seconds or so. I've been practicing single dosing & it takes around 6 seconds - very little retention, although isn't officially a SD, it can be done. Mine came with the small hopper- from Clive Coffee.

It might be more for a grinder, but it's not that bad. You'll like it.

To me, the 75 would make the most sense of the atom grinders. The only thing (apart from the higher cost) would be that it is so blazing fast. If I understand correctly, the timer has a resolution of 0.05 s, which translates into about 0.3 grams. So I would worry a bit about variations in the dose. Or maybe this is not a problem at all? Would be very interesting to hear the thoughts on this from current owners.

The dose is actually pretty stable, within .1 or .2 grams usually. One variable that effects dose time is how full the hopper is. The beans feed a little faster when the hopper is full of beans pressing down, and a little slower when getting empty. Of course, you also need to change the timed dose after making a grind adjustment. Over time, with experience, you start to get a feel for how much to adjust the timed dose when making a slightly finer or coarser adjustment.

As someone else has said, the Niche Zero is a great option. I'm not sure why you say there are no good single dosing grinders in your price range.

But, it sounds like you're leaning towards hopper fed. When I got the Atom 75, I was under the impression that you could single dose or hopper feed it. That's not the case. Grind adjustments absolutely require 10g or so before they take effect. If you go into it knowing it's hopper fed, I think you'll be pleased. I wouldn't obsess over burr size of you're budget conscious. The Mignon Specialita (55) and Atom 75 tasted very similar to me with their stock burrs.