I played some more with this yesterday, and I have to say I'm still impressed. I cut 4 layers without a problem; I can see where it's feasible to stack more layers than that. You use whatever rotary cutter you like with it, so as long as the blade is sharp the additional layers aren't a problem. The Speed Gauge sits 1/2" above the cutting surface, so to check your strip width it actually has to move downwards on just a few layers of fabric.
I'm trying to be good and finish the quilt I'm working on before I cut out another one, but it's getting harder and harder to be good.... :wink: