It took about 6 tries to get it dialed in for the AeroPress. I started at full-tight (finest grind), and worked larger. Grind a bit, dump out, compare to the "right" size, adjust, repeat. No biggie, these don't have to be 14 gram grinds - 1 or 2 grams will do.
Once I got it dialed in, I dumped in a 14 gram scoop of beans, and cranked for 75 seconds. Pressed a cup - very nice, very smooth - just like I like.
This is a completely usable grinder, and it's quite attractive - if you like canning jars, wood, and blacked cast iron. It would not look out of place on a shelf in a log cabin in the woods (of course, neither would a wooden box coffee grinder). The rounded jar is easy to hold in one hand while cranking with the other, where my experience with box grinders has been otherwise (boxes have pointy corners - rounded jars, less so). Further comparison to box grinders, there is enough vertical clearance between the top of the assembly and the crank so that your fingers are unlikely to get pinched (unlike some box grinders in my acquaintance).
I have completely dismantled the grinder (a little patience, undo 4 screws and all the pieces come apart). On mine, the wooden base that houses the canning jar lid had several rough spots inside the center area where the grinds come out. I used a piece of sandpaper to smooth this out (coffee was getting stuck there, which I didn't like). The grinder looks nice all put together, but inside, the fixed burr casting doesn't quite sit centered on the wooden base (on mine). This is a very minor quibble. If handmade uniqueness adds to the charm for you, great. If it doesn't, you've been advised.
As the grind is adjusted coarser and coarser, there is free play introduced in the shaft/rotating burr assembly. A moderate downward pressure should alleviate this somewhat, and help keep the grind more consistent. Finer grind settings, there is almost no play, and a very consistent fluffy powder is produced.
The rather significant mass of iron for the burrs means they shouldn't heat up much under "normal" use - go ahead and grind, you won't scorch the beans.
Some espresso gurus have said that sharp burrs are necessary for maximum excellence. The burrs in mine are rounded - they are cast and used as is, not rough cast and then machined to final shape. Machining isn't cheap, and it would easily add 50% or more to the price of the grinder. The grinder may smash up the bits fine, but it may not cut them. It is up to you to decide if this will work for your espresso machine and quality standards (I'm doing filter at the moment, so I can't test - unless you want to send me your espresso machine for a month to test with).
Turning the grinder is very easy - it requires very little force to turn. Consequently, it requires many turns to grind a lot of beans.
This was purchased as a traveling companion for the AeroPress. If I'm on vacation (or camping), I don't mind taking ten minutes to make coffee. If I'm going to make a lot of coffee, I'll probably figure out a way to spin it with a cordless electric drill.
These used to be called "rustic coffee mills". They're everything you might expect from 1860's hand grinder technology. This is not to say that it's bad - I like the coffee I'm getting. Don't expect modern miracles of European engineering as applied to coffee grinding in this product.
Now, the important part: if you plan on having electricity available to you and don't want the romance of hand grinding your coffee for 5 minutes, get something else (like a Baratza Maestro). I would not buy this as my primary grinder if I had electricity available. I got this as a secondary grinder, for when I'm traveling and may be without electricity. For that purpose, it's great.