I received my Jettin V. Tool but I am yet to try it out. It is good quality, probably not as nice a tool as the factory offers but I think for holding the variator in place while I loosen a nut it will work just fine. I also purchased the clutch holding tool.
When I do my belt and rollers I will report fully on the experience.
I guess I looked at it this way: $140 is not unreasonable for a specialized tool, but not really worth it unless I was working on Vespas all day long.
Take the extra $75 and apply it to other tools that will make your life easier when working on your Vespa.
Craftsman and Snap-On make great tools and since they are not specialized for one application I can see spending the money there.
Check out
http://www.griotsgarage.com/ for some cool tools and other things to spend $ on.