In the eight years I've been grinding my own coffee, I've burned out the motor on three grinders: a cheap blade grinder, then a Cuisinart burr grinder, and finally a Capresso grind 'n brew. Either consumer-level grinders are poorly made, or my workload of 4-5 pots of filter coffee per week plus the occasional enemy (no space for a wood chipper in my city apartment) is too intense. Having spent more than $300 on now busted grinders I decided to investigate what it would take to acquire a grinder that I might reasonably expect to last for a decade.
The Rocky has commercial grade grinding burrs and is rated at 7.7 lbs per hour. Rancilio refers to the Rocky as "quiet during operation", and maybe it is in a relative sense, but I've yet to find a device that crushes things at a volume level approaching "serene". It is slightly less obnoxious than my previous grinders at close range.
Though I was sufficiently assured that the grinder would stand up to my usage, the quality that tipped the scales towards the Rocky is one most coffee nerd sites don't mention: height. At 13.8" tall, the Rocky is much shorter than most prosumer grinders, and it was the only grinder of its quality that fits easily under my shelves. I've had it for two years at this point and it still grinds as if I'd just taken it out of the box.