As much as I appreciate new tech I wouldn't prioritize shifting when spending my money. The shifting on most drivetrains is so good these days that the added value of this is small compared to high end suspension or wheels. If i was still racing I probably would go for something high-end (read: Shimano XT or XTR) to get the shifting under max power benefits though.
One thing though, there is so much focus on shifting under power but what about shifting when coasting? For winch and plummet riding I think that would be more beneficial. I find myself half-cranking quite a bit to get shifts done so that I am in the right gear when the terrain changes. A gearbox would obviously solve this issue, but comes with other issues.