On razors I doubt there is enough steel removal to show effect. My experience is with kitchen knives, Lots of metal removed and all.

I would be interested seeing the stones after equil use with the same steel. I'll have to get with my group of knife knuts to see if there are a large number of these stones available for a side by side test.

The only other thing I'm not crazy about with the glass stones is how thin they are. I'd end up burning through them to fast to make the savings worth the effort.