Noise level is a subjective thing, Ive found. Yes, my em6910 makes a noise, but would I call it a "jack hammer"? To me it purrs like a kitten! However, I do hesitate to make a coffee at 4:30am before morning shift for fear of waking my neighbours!
It is a little noisy at first, when its doing the pre-infusion thing, but then it quietens down as the pressure is applied to the shot. I actually find this quite a satisfying sound -- but then, I am in love (or lust) with my machine! :o
I dont find it any noisier than the em0480 grinder.
For your own assessment of the noise, check out this small vid of my 6910 on youtube:
Mind you, those new Gaggias look pretty damn good, too!