It's so easy to get into aerodynamics theory and arguments about who's got the better tip that its easy to forget what matters.
The line pilots that reported this effect are happy with it. They are probably experienced pilots who have flown similiar conditions in different types (all of which blow dust into a donut, yet don't seem to offer the benefit they've reported). Lets respect them by agreeing that perhaps they have found something unique.
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As far as the blade tip argument, here's my 2 cents. The S92 has about 20 years of development and technology that BERP didn't have. If S92 isn't better then something is very wrong. Similiarly, BERP IV has the advantage of potentially being better than the current S92. That's just how technology develops.
As far as timing and design similiarities, that's easy to explain. Physics doesn't stop at political boundaries. The physics that gives benefits to the BERP blade also work for the S92. As far as timing goes, the demands of the helicopter are very similiar because they are competing in the same global market. This means that the desired performance enhancements are quite close. The timing of producing similiar designs has much to do with the technology that's available. As more is known about composites, and more confidence is generated with their use, designs will start using them. I expect that making a tip like these out of wooden blades would have required so much weight that the gains in performance were lost to AUW.
As far as I know, BERP was the first (at least commercially, not sure about development). That makes it exciting. Bragging about its performance now could sound a lot like bragging about the speed of my 75 MHz Pentium. At its time Pentium was impressive, now I'm left behind with an 866MHz Pentium III. AW appears to understand this, hence the development of a new series of BERP blades.
Matthew.