I really can't see auto glym being any better than anyone else's clay. I really can't. They're way behind in most things car cleaning these days. The only thing going for it is it's availability, but meguiars is quickly catching up. I honestly haven't used anything autoglym for about 3 years
I'd have to agree with JPC, everyone else has had clay out for ages, AG have only just cottoned on to the fact. They'll be bringing out a quick detailer next......
The one and only AG product I use is their Autofresh, spray it underneath your mats and it makes the car smell lovely.
Megs kit is far more advanced and user friendly, and Zaino is even more fantastic IMO