I'm buying Lelit Elizabeth espresso machine. I pan to pair it with a single dose grinder but having problems choosing the right one. I'm after top quality, easy use, zero retention (or close to zero). Budget up to 700 eur.

Right now, i'm picking between Niche Zero (hard to get), Eureka Mignon Single dose (hard to get), Probarista G-iota with built in SSP burrs.

Any other that i should consider?

I don't know what's available in Slovenia, but the Baratza Vario with ceramic burrs seems to be a popular choice.

Though not single dose by nature, it has low retention.

I've been going through the same decision lately. It's tough. I've read as much as I can on any of these grinders.

If single dose is what you're after (same as me), I'd stick with a single dose grinder. FWIW, Eureka is actually coming out with two single dose grinders, the Eureka Mignon Oro Single Dose, and the Eureka Mignon Zero. The latter is basically one of their espresso grinders with their single dose hopper and blow up system. It's also cheaper than the Oro SD and has smaller burrs.

The other question that you'll need to ask yourself is if you need to brew any other types of coffees either regularly, or from time to time. We do, and that changes the grinder landscape. I've asked repeatedly and Eureka grinders owners assure me that one would NOT want to dial back and forth between different grind settings with their small dial. They say you can't be assured that the spot you were on will give exactly the same results and a very small movement can result in a large change in espresso shots. Great if you'll only ever need espresso, not so great if you need filter/French press/cold brew, etc. If so, the Niche is likely your best option or as an outside possibility, the DF64 (though I've heard mixed things on how easy it is to be repeatable with settings on that one too). The Niche get great reviews for being easy to dial in, easy to switch to other grinds, and easily repeatable settings.

Depending on what you're looking for, the only other upcoming grinder that I know of is the Kopi Deva. Currently in crowd funding but has great reviews. There were a couple of small requests from reviewers and Kopi has already assured them that the changes are happening in the production run. It's very different from anything else I know of at the price range as you can use SSP burrs (takes 64mm flat) AND you can change the grind speed. Unusual for the price range. I'm not sure of you preference on burrs or taste.

Hope that helps a little. Best of luck with your search!