In reply to zebedoo: Might you be able to define 'issues'?
I have nepal extremes and Airtechs (new matic) work perfectly - As I have small feet I find the super asymmetric linking bars give a better fit.
Be aware that in the past year or so grivel changed the design of the airtech to decrease the distance between the tabs holding the plastic toe cradle. This means that the newer ones have significantly more front point protruding from the end of the boot which makes ice a lot easier. I have both types and the older ones are great for mixed but a little awkward for ice.
