I have G-14's and love them. I can't say I've put them through the same rigors as vw4ever
However, I did have some issues with the toe bail fit on LaSportiva K4S boots and spent a bunch of time on the phone with Grivel about newmatic versus crampomatic. The fit challenge was resolved.
They were pretty agnostic about which was better, but did point out that the front plastic part on newmatics will need to be inspected and replaced more frequently than a metal bail. Plus it weights a smidge more.
I' ve used them on Scarpa Alpha's, La Sportiva Makalu, LaSportiva K4S, and my Dynafit AT boots. It never takes me more than a minute ot make the appropriate adjustments to get a nicely tuned in fit.
Hope this helps.
-r