Even an old first gen N-trig like the one which worked with the HTC View tablet works perfectly with the R7. Two buttons, pressure sensitive. Not sure what the new ones offer that is different? Perhaps better palm rejection? That works fine on the old one too. Who knows?
Does the Acer pen offer any sepecial hardware or drivers the Sony version does not?
I don't think there's anything different in the pens themselves. I believe the N-Trig digitizer technology and/or drivers have been improved. The pen just works out of the box. There are no additional drivers that come with the pen.
Frustration is the topic of the day. after spending $50 for the for the Active Stylus R7-572, I can get it to work. I see there is a full 4/a 1.5 volt battery that was supplied with the unit, yet no connection to my touch screen, yet. Maybe it's missing a driver, or I just don't know how to work with it. I do see there is current coming out of the business end of it.
I've pretty much given up on the active stylus as a waste of money. Nothing seems to recognize it as anything other than a plain old stylus, and there is no documentation at all on how it should work or be used.