I played around with Bumptop a little bit when it came out but I have to say that I quickly removed it as I found it to add no value what so ever.
If anything this seems more like a talent acquisition than a technology acquisition.
On the other hand, I thought that a side-effect of 20 years of acclimatizing to the industry-standard GUI might be difficulty switching to such a strange, physics-based 3D interface. It may be another issue of learning curve vs. post-learning benefit. I didn't give it enough time to really tell.
I'm not buying into 3D interfaces represented on a 2D screen. I don't believe 3D interfaces will succeed until they can be holographically projected around me a la District 9.