Reputation. This may not be persuasive for some, but for others it's all we have to go on, at least at the begining.  It's satisfying owning a product that is widely thought of as the very best at its price point.  The best way for an "average" coffee enthusiast to learn what a good grinder does is to use one every day. I'm learning to appreciate and use the infinite adjustment capacity, proving that a quality product extends one's learning curve rather than shortens it.  I notice that even the so-called negative points have, for me, very simple work-arounds.

We Mini owners have to work hard to come up with a few serious negative points.  OK, the grounds can miss the portafilter, the hopper is huge and may not fit under a cabinet, the cord coming out the left side is dopey. That's about it.

The Mini is clearly the most widely and apparantly positively reviewed consumer grinder.  If I have anything unique to add let me get right to those "negatives."  First, something I still haven't resolved is that I'm still intimidated about dismantling the burrs for more rigorous cleaning, and nothing I've read has made me feel confident yet. Easy to procrastinate on something like this.  My other comments are all in the area of "functionality" and ease of use. These are simple matters.  One that many others have mentioned:  It's not necessary to use to use the hopper at all.  Like others, I rest my tamper on top of one or two shots worth of beans.  I thought I would occasionally put the hopper back on, but I never have even for larger groups. There are a couple of other modifications that have made my use of the Mini even more satisfying: I loosened the two screws holding the portafilter bracket.  This lets me continue to use the bracket to "lock" and align the portafilter but also lift up and slightly to the left--closer to the doser shoot.  I lose many fewer grounds this way and don't have to be so cautious with the doser to avoid throwing the grounds off to the left.  Finally, I do not use the plastic tray that's designed (I suppose) to catch the spilled grounds.  Instead, I slip a 12 inch square chemex filter paper under the Mini's front feet.  This makes for a much neater use, and I rarely have grounds to wipe off the counter as I did with the provided catcher.  I'll use the paper again if until it's not messy or wet from the portafilter.  Finally, there's some question about how long Mazzer will continue selling the sub-$400 Mini, so grab one in a hurry.  
    UPDATE:  Not exactly 3 months, but I want to leave and revise the statement above about being intimidated by cleaning the Mini.  If reading many posts in the discussion groups did not ease my concerns (stripping the threads, resetting the arrow sticker, etc.) rereading the manual did!  I followed the straightforward directions in the manual, I took out the pieces that were removable, cleaned them with a bamboo kabob skewer (my recommendation), put it back together just fine.  Maybe I just got lucky, but it's a procedure that I'll repeat every couple of months with care but without concern.

Bought at Whole Latte.  No problems.  Courteous.  Since then, I'd recommend 1st Line for outstanding service.