been using the DF64 (aka G-iota, Solo, Turin) grinder for 3 weeks now..  Ran through almost 3kg of failed roast beans to season the burrs.

Am pleased to report it is a pretty solid single dose grinder for the price.. Mine came spec with Italmil steel burrs and my espresso grind setting is around -3 to -5 past the 0 mark. My zero point is about -10 (kinda hard to see because there's no mark). According to another forumer who swapped to SSP grind setting becomes more manageable due to SSP burrs' thickness. Burr touching point is on a higher ring number (10-15).

Grind rentention / grind exchange is very consistent... weigh in 20g, output is between 19.9g - 20.1g consistently with the use of the blower. I found that sometimes a rogue bean or two will bounce around on the burrs instead of getting ground up with the rest. Have to keep pressing the blower couple of times to get it ground up.. Do other users experience the same?

I Did blind taste of the DF64 and Breville Smart Grinder Pro with a couple friends (properly dialed in shots) and all agreed that the flat burr produces a shot with more clarity and easily distinguishable flavors compared to the muddled SGP shots. Waiting for SSP unimodal burrs to be restock at Lamarsa coffee and gonna swap it out.

For the price sold by J Cofffee, it is a very capable grinder for home use. Solid build quality and easy to maintain. Just some minor niggles and kinks which can be worked around.