I'd recommend a day in the 29er saddle. I'm based in Watford if you wish to borrow mine for a ride-out.
When I did buy, it took a while to really grasp and adjust to the different riding style, not that many had 29ers even 15 months ago (what does that tell you in its self?).
That was on the back of me riding for 2x MBR magazine articles as a "non-magazine test rider" & some might recall said article from a couple of summers ago – and whilst I had parity with the 29ers on said rides, the other tester, Ian, did not.
In many ways, the question is not relevent.
If you have been out racing and riding the summer's events, be they the Bristol Bike Fest, Keilder 100, Polaris, the Gorrick, MM, SITS, Bonty, or if you spend you time at Afan, Dalby and Glentress (forgive me as I do not know your riding history) then you will have possibly made up your mind, after all so may people are taking a 2nd bike with a bigger wheel means there is a real shift in the mountain bike sea-state.
One caveat I would add is that some magazines and certain web forums are more atuned to this change than others. So, in response to the original post: it is still one that no one here can answer for you as such. You have the information, but you need to try one out, possibly? If your ultimate goal is out-right speed, then as has been observed, you'll be better off on a 26er on the more tech' trail centres, but for may other circuits, the 29er will simlpy muller a 26er.
Best of luck. Can you let us know your thoughts if you do make the plunge?