I've had the opportunity to get out and about on the Planet X Cyclocross Disc and Canti Pro Carbon wheels properly now - I've had some nice long rides across the moors as well as sharper blasts round my local cross training grounds. There hasn't been much proper mud as such (despite the fairly miserable summer) but their performance on a range of surfaces, from grass, to moorland tracks to a purpose built mountain bike trail has been surefooted and accurate.
I realise that a carbon cyclocross wheel isn't necessarily designed to ride rough tracks or even the Red route at Gisburn Forest, but actually it's a great test of how a wheelset performs under stress, and in challenging conditions. I've loved the fact the the only thing holding me back on these rides has been the nagging worry of puncturing a nice FMB tub and not the worry of the wheels going out of true or breaking a spoke.
Planet X say they would be suitable for fast mountain bike use and with a fatter 45mm tub they clearly would be. Even with a 32mm cross tub they soak up bumps and rocks without deviating from the line. This stiffness will translate well to mud in the winter cross season and comes from the 24 hole 2 cross build on both front and rear. They accelerate so quickly too, even when the ground is bumpy - something some wheelsets struggle with as the bumps can sometimes feel like they suck energy out. Not so with these.
Their lightness and strength mean I have no qualms about using them for the 3 Peaks cyclocross in September. Crazy? Well not really - they feel perfectly strong enough and the Peaks is all about avoiding punctures, and not taking crazy risks on the descents. Mechanical sympathy wins every time over blinding speed that flirts with a puncture on every rock. Tubs help hugely in this respect too. The fact that they are very light for a cross wheel means they will also help considerably on the never-ending climbs in the Peaks.
Watch out for a forthcoming video on tub gluing featuring these wheels.