Hi Russ,
I cant say that I noticed any comparison tests having been done between Gecko dampening and fitting a mechanical device.
Obviously some drivers are better than others at reducing the mid life crisis and as Gerry said Xylotex is pretty poor at it.
I don't have any Gecko's at present or else I would try a comparison. I have, however, found that with the same motor (without the damper fitted) a Toshiba chipped driver performs better than an Alegro chipped driver - backing up what Jeff Birt was saying in another thread. Fitting the damper there was little, in anything, to chose between the two.
Tweakie.