Best grinder you can buy
This grinder is only a few hundred dollars more then other grinders, but it is quiet and fast. We had a Mazzer Super Jolly before. It took 12 seconds to grind a shot, the K30 task 3 seconds. The sound volume is so low enough that you don't have to raise your voice to talk over it. These are really big selling feature if your coffee bar is near where people are working.
The other big difference with the K30 is that it takes much less adjustment as the coffee beans age. It goes for days without the output varying by more than a few tenths of a gram and the shot times are within a few seconds.