Seems to be a lot of claims as to the supposed benefits of 29ers, and I am sure they are better suited to certain types of terrain and riding, but I have yet to see any conclusive proof or scientific evidence that they are overall 'better' than 26ers.
I agree its horses for courses.
29ers will get through the super tight and twisty stuff but they will be a little slower.
Most races do not have lots of this type of riding.
Neither do any of the trail centres that I've visited so far in North and South Wales.
That type of trail is not good for fast flowy riding. Not that much fun really.