Heavy, all-metal construction.  The bean hopper was also very thick glass.

Couldn't grind fine enough, could be dull burrs.

My 30 dollar Mr. Coffee Burr Grinder died about a month and a half ago, so I started on my quest to find a new grinder.  The Mr. Coffee lasted about 6 to 8 months....and it worked well, and it was only 30 bucks.  After reading a bunch of reviews on here, I thought I would try the Starbucks Barista Burr Grinder.  I took it home and tried it, and absolutely HATED it.  It seemed like whenever I pulled the ground tray out, the grounds would fly everywhere because of static.  Here wait...i'm writing a review for the proline, not the barista.  :-D

So, I took the Starbucks one back and decided on the KitchenAid ProLine Burr Mill, again, because of the high reviews on here.  I took it home and I loved it.  It worked great for french press and drip coffee.  Then, I got a new espresso machine (Rancilio Silvia).  I cranked up the KitchenAid to number '8', which is the finest grind, and out came the grounds.  I let my Silvia warm up for a half hour before all this, tamped to 30 lbs, and pulled the shot.  To my surprise, it took 12 to 13 seconds for the shot.  While this was ok, the shot should take an average of 25 seconds.  

I have been trying all different things for the past week, and all I could get was the 13 second shots.  The only way I could get a 25 second shot was if I adjusted the grinder so the burrs would rub.  But then, the manual says don't let the burrs grind or else they will wear out.  I tried to make the machine stepless, but this didn't help too much either.  It helped, but I still didn't have a warm fuzzy about the machine.

I then called the KitchenAid tech support, and wasn't thrilled with the support either.  I spoke with the lady for about 20 to 25 minutes, and when I hung up, I wasn't any better off with when I started.  She didn't say anything about "I'll send you another set of burrs", or "you should take it to a repair shop", or anything like that.  I then wrote one of the admin's on the KitchenAid message board and asked her if she could send me another set of burrs because of my problems.  This was two days ago, and I still haven't heard anything back.  

In the end, I returned it to The Great Indoors and spent a little more money on a Rocky.

While The Great Indoors is a little more pricer than other stores, I can't say enough good things about my experience there.  I already recycled the original packing box so it was gone.  I had the manual, grinder, and the cleaning brush, took it all back to the store and they returned it with a smile.  Since I bought it about 32 to 33 days ago and didn't have the original packing materials, I thought for sure they would at least take the 15% restocking fee.  But they didn't, and they were so nice about everything.  I would DEFINITELY go back to the Great Indoors and buy products from them in the future..even if it does cost a few more bucks.