I had purchased the stainless mitre box almost a year ago. The cutter I had wasn't tall enough to work with it, so it sat on a shelf for a year. I finally bought this and am so glad!
It's definitely durable enough to cut through cold process soap. It's easier on my hands and arms than my other system was. Makes nice, clean cuts and no more trimming of bars is necessary.
Love it!

Pros:
-cuts straight
-cuts cleanly
cons:
-a little flimsy

This device deserves a better rap than 1 star its actually not that bad unless you're cutting supper dense soap.

This cutter is too flimsy. It actually bends and moves when using it in the miter box with M&P Soap.