Supposedly the special thing about the Vario is a near-180 degree flood that evenly fills your vision -- i.e. you get full peripheral vision, rather than a cone with a central hotspot. I don't think any other caving light does this. This could be a killer feature or a gimmick; you can't know which without trying it.
I have its ancestor, the original Ultra, and it's a good light -- but too expensive. If you want something "programmable" then the Ultra lights are unsuitable. On the other hand, there's something to be said for simplicity too.
The Vario looks like a much better caving light than its predecessors, but similarly expensive. And like most mega-lights, battery lock-in means that it's now the only affordable upgrade available to me...