I have been discussing nutating tamps with our staff. Then I found this post. (I still recommend nutating tamps because... coping my comment:)
"I find that "nutating" (perhaps it should be "precessing") produces a more even tamp, at any level of fineness. My thought about this tends to be that it increases the probability that larger spaces in the heap of grinds are forced to cave-in. I've compared nutated and non-nutated shots, the latter taking 10-15s longer to reach the same brew ratio... and often enough the former will cone more symmetrically, and taste cleaner. Does anyone else have similar experiences?"
Perhaps I just work in a cafe where most shots are shorter in duration and messier in coning. Who knows. No time to collect all that data on everyone else.
Well, it's not like Perger invented it (it's not a hard thing to invent). I was making coffee like that in 2008. I just find nutation to provide a more even tamp. ;)