OK, so this is not really a review, because the KMM30 is the most-reviewed burr grinder out there.
Go ahead and read 90 pages of Amazon reviews for it, I dare you.
I double dare you to buy the thing after you are finished with the reviews, then
So it has problems with static and dust, and grind unevenness, and everybody knows that
Some people are intent that an old shoe or a bag of stones works better than the KMM30
But IF you have bought it to use for espresso, here is the secret recipe.
#1: do the mod: remove bean hopper by puling it up with your thumbs , reseat the white indicator collar (unclip the 3 clips all around with a thin screwdriver), and set it to a new zero point by ear - i.e. until the burrs touch, then back up a click. NO cutting, NO screws, NO breaking anything is ever necessary. Proceed slow, it's really simple
#2: this I have not been able to find anywhere, but this is IMPORTANT-
to cure problems with static and dust, do the following - take a tablespoon of ground coffee in one hand, take the KMM30 in the other. Feed the ground coffee into the coffee chute like you are feeding a baby or a cat. Make sure it stays there, but do not tamp. Now carefully put it back on the table and never clean the chute with the provided spoon.
What happens is that the coffee in the chute does not allow the new ground coffee to fly out and stick to the bin, making it all a static charged-mess. Also, the grind gets more even because coffee passes more slowly and accurately through the grinder.
So basically it need to stay semi-clogged, or lightly "stuffed". Cleaning it is a bad idea. When it unclogs by itself, repeat the procedure #2
#3 save up for a Gaggia MDF or Rancilio Rocky, enjoy your espressi in the meantime