Nice stable grinder, grinds very even and fast. The worm gear is extremely fine grained, so you can set the grind very accurately. Solid build quality, this grinder will last a lifetime in a home environment
Negative Product Points
The worm gear is extremely fine grained, forget switching between grind types (Espresso to FP for example), it would take a couple of thousand turns. The set screw for the hopper tends to hit the worm gear assembly if you turn it enough, doesn't happen during normal use though.
So I've had this grinder since 2010, and I must say I'm very pleased. The reason I got this particular model was that I wanted a grinder with large burrs and better build quality than the consumer stuff I had been using. And the M7 has 75mm burrs on it, and I couldn't afford the conical versions, so I chose this one.
The build quality is in my humble opinion second to none, it's extremely solid, everything turns and clicks very smoothly, and it doesn't have anything that I'd consider a major flaw. The finger guard inside the doser and the external tamper thingy are of course stuff that you want to remove, but that doesn't really take any time to rectify (the tamper is detached for shipping and the guard is attached with two screws that are easily accessible).
The M7 is very nice to use, it has a nice chunky on/off switch, it grinds enough coffee for a double espresso in approx. 10 seconds, and doesn't vibrate very much at all. The chute between the grinder and the doser tends to retain quite a bit of coffee, but it's very accessible and therefore very fast to clean. The dosing mechanism is very solidly built, so you can do the smack-smack-smack routine without fear of breaking anything. The doser wipes itself very clean as long as you brush down the spindle in the middle, which is very nice indeed. The stepless worm gear grind adjustment is both the worst and best thing about this grinder, if you do only espresso it's perfect, you can adjust the grind an infinitesimal amount, but forget switching between FP and espresso on the fly. If you want to do that, get the stepped adjuster instead, and skip the doser.
It's not the quietest grinder in the world, but then again this is a commercial grinder, with a 1,4 kg hopper on top, so it's kinda expected. I don't really mind since it's not shrieky sounding, and it only on for ten seconds at a time anyway.
Espresso Coffee Shop (espressocoffeeshop.com) is a great retailer, they ship straight out of Italy, they respond to email fast, and they even emailed me when the grinder I had selected was out of stock, with the option of switching colour or waiting for a later delivery (with an expected delivery date). Shipping was free due to the value of the order, they shipped it to my door on a shipping pallet, which was very nice. I've bought from them before as well, and they were equally great back then as well. Their prices are also very nice since they ship from Italy. I'm in Europe, so for me voltage wasn't an option I needed to concern myself about, but for you US guys I've noticed that they offer different voltages on most machines, and they also have the same free shipping policies for overseas orders.