Aye, I have indeed. The Zirkel is a nice bag, warn, roomy, nice length, good hood. There is a weight saving to be had, but you have to be careful what bag/mat combo you go for.
The mat I'm using is the winter one and although it's lighter than the Theremarest equivalent the packsize is much bigger. Another thing is bag length, the steps up are different from European ones. At six feet the long size fits me fine.
I'm doing a daft stunt with the kit during the week,when I've written it up I'll stick a link on here to it.
There should be quite a few independants with BigAgnes kit in the spring.