I thought they were close but it looks like the muppy is .045 thicker and a half inch shorter?
The handle on the Vex is shorter too. The Vex blade (or cutting area) is measured from the front of the choil not the handle. The Vex has more blade less handle and is a better design for most of my tasks compared to the mudpuppy. I wouldn't consider them anywhere close to the same size.