Obviously Graupnerfan you've never experienced The old TF white plastic nylon props. If any wood props flexed as much as they did they'd disintegrate.
And don't confuse tip tracking with flexing.
All Props will flex to a certian degree depending on the material they are made of and the diameter of the prop. Other factors will come into play also, blade shape, thickness, rpm,etc,etc.... Even props of the same manufacture can be different. Depending on the batch.
In the long run use what ever prop your happiest with !!! And it doesn't hurt to experiment with different diameters and pitches to find out what pulls your model thru the sky the way you like.
Good luck and have fun !!! [&:]