The so-called "variable ND" filters are really, really popular with the new generation of kids shooting video with their DSLRs. They don't seem to understand that those things are actually polarizers though. It's an easy "turn a ring and look at the screen and shoot" vs. having a set of NDs and a matte box.
Looks like you'd have the same issues with this product (blotchy skies, dead skin, etc). But the idea of balancing full-on opaque UV with some amount of visible light is interesting - I don't shoot full-on IR because I tend to be "seen one white tree, you've seen 'em all" and prefer deep red filters, so I'd like to see how many looks could come from the same scene. Would be great to frame up a composition and intuitively know the IR-to-visible balance that would serve your vision for the final print, wouldn't it?