I'd consider the shop type fixed cup tools (Campy, VAR, Cobra - which are the ones I've used) functionally equal for standard -normal torque/36mm cup- applications.
The big advantage of the VAR seems to be the huge range of sizes for the tool insert: 16.1, 35.1, 35.5, 36.1, 36.8, 37.8 and 38.1mm are available to this day.
The distinguishing feature of the Campag - aside from being pretty- are the flattened sides of the cylinder, which allow you to mount the tool in a vise and turn the frame. This makes the use of extentions on the handle unecessary and thus prevents bent handles (which I've seen on both VAR and Campa models in shop use).
Tobit Linke, Dortmund, Germany