I've had very good luck with regular old plastic wrap, worked better for me than the Invisigrip. Also, I recently read somewhere, that using a narrower ruler, say a 3" compared to a 5 or 6" would give you better control.
Quilter's Rule sells adjustable rulers that are real nice for strip cutting. They're made with a special lip that makes very accurate cuts. No affiliation, just a satisfied customer. You can look at them here:
http://quiltersrule.com/rulers/qr-westalee.html
You've received many great ideas here. Great thread! :thumbup: