It may be an irrational exuberance sort of thing....
I have one of these, and after you complete a receiver you really feel like you've just machined a swiss clock out of metal, when in fact all you did was connect the dots on the template/jig.
It's hard to describe, but it really is pretty cool.
This is the first jig I've owned so I can't tell you whether it is better than X or Y brand.
But I now realize that I am a master machinist, and will begin work on my oscillating overthruster next.