If I could give this pepper grinder 6 stars, I would. I just received the grinder in the ,AIP today so I am unable to comment on its durability, but I will comeback and edit this review if I encounter any problems. But here are the things I can say about it:
1) it is larger than the pictures make it appear to be. It is about the size of a high quality LED compact flashlight, and is just smaller than the diameter of an old fashioned silver dollar.
2) the hole for filling the grinder is much larger than I had expected, nearly the size of a quarter. I am confused by the reviewers who said that it was difficult to fill. I had no difficulty whatsoever in easily filling it with peppercorns. And the ring that you twist to expose the hole has a good, tight fit making it hard to believe that one could unintentionally open the hole and spill peppercorns out.
3) but by far, my favorite aspect of this grinder is the incredible range of grind settings and the utter ease with which one can change the grind settings thanks to an ingenious spring-assisted thumb screw on the bottom. Turned as far as it will go clockwise, the grinder produces the finest grind (I would almost call it fluffly) I have ever seen from a pepper grinder. Turned as far counterclockwise, it renders a very coarse grind that I would describe as "cracked' peppercorns.
I have gone through 3 grinders in as many years, ranging from the oxo grinder up to a zassenhaus (please excuse me if I have misspelled this word) and this is the best by far and is a fraction of the cost of the most expensive grinder I have ever owned. I can't believe that I am this pleased over the purchase of a pepper grinder but I am. I highly recommend this grinder to anyone who has given up on finding the perfect grinder, because I think you will agree that's exactly what the Unicorn Magnum is: the perfect grinder.

Bought this a day after visiting a high end steakhouse and commenting on the output and ease of their pepper grinder and of course was a Unicorn. We love pepper at my house. Really love pepper. On everything. This grinder puts out a ton of perfectly ground pepper with minimal effort and adjustable grain size. The little coaster is a nice touch that keeps the table cleaner. Loading is easy and it holds more than most which is great when you use a lot of pepper. By far my favorite grinder ever used and now have two, one for cooking and one for table. Can't believe I'm this excited about a pepper grinder, but I'm thrilled when a tool does exactly what it's supposed to do with perfection every time.

Very good pepper grinder, certainly better than most of the dozen or so I've had.

PRO's:
- holds about 4 oz of peppercorns, fairly large capacity in this compact device
- very easy to fill, just slide open the hole on the side with grinder laying down
- when closed, fill hole cover stays closed
- grind is extremely adjustable from almost powder to large cracked pepper nearly half of a peppercorn
- requires very little turning, say 1/4 turn, to get a lot of ground pepper
- turning is easy and can be in both directions. Clockwise grinds, and counterclockwise clears grinding burrs
- comes with a plastic base to set grinder into when not using it

CON, and why only 4 stars: the entire grinder is very, very smooth plastic and slips in your hands if only the slightest bit wet or greasy. Yeah, I know, wash and dry your hands before using the grinder, but seriously, a knurled top or bottom or both would have made this the Best. Grinder. Ever!

This thing is pretty awesome, it cranks out the pepper! I was looking for a new grinder because I was sick of cranking forever to get half a teaspoon of pepper but this totally solves that problem! Even though it's plastic it has a good heft and solid feel to it. The all metal grinding mechanism should last me for a long time to come. Other people complained about the fill hole being opened accidentally and spilling peppercorns everywhere and I can see how that could happen but it's like "DUH" when grinding just hold on to the bottom half instead of the middle! Easy peasy! You don't have to be a rocket scientist to figure that one out! We love this grinder!

We have owned and used the PEPPER and SALT grinders continuously for over 4 years - and not gently or carefully mind you! We are ordering another set because our son keeps running off with them to his computer room (where he eats) because he loves them too. These grinders are SOLID - and I never worry that they will wear out or break... which is far better than every grinder we have owned before these. The pepper grinder is absolutely perfect - highly adjustable and easy to tweak when I want a different grind! The salt grinder works well, but salt can clump if one is not careful to keep it dry. The grinders come with bases... and if they are used, they help a lot. However, we have occasionally flooded it with a spill - and that gums it up a bit. We've found it can be dried (a paper towel) and cleared easily... but it will not work well until cleaned up if the salt on the bottom if it is allowed to get damp/wet. No amount of "continuing to try to grind" will fix it with intervention with a towel. But - hey - salt is that way! I easily recommend these compact and durable grinders for serious kitchen usage - they have proven solid and indestructible in our kitchen (4 years and counting).