This week I've ridden a technical, undulating section on both new (Boardman FS Pro, 650b) and old (Whyte JW4, 26"). I cleared it both ways on the Boardman but failed both ways on the Whyte. The Whyte seems to jar on the rough bits where the Boardman skips over. It's down to the individual trail section, though, because I know other places where the opposite is true. I certainly know circuits where my money would be on the Whyte to get round quickest. 7 years ago, when I gave up on my first JW4, I found it's replacement, a Voodoo Canzo 26er, was around 15 seconds slower on a 10 minute red trial which forms a circuit.
It's horses for courses but slightly worrying that 15 years hasn't produced a bike which is faster in all situations. And don't get me onto pedal strikes with modern trail bikes. :evil: The BBs are just too low and shortening the cranks robs you of torque when you need it. :cry: Better post this before my blood starts to boil!