Carbon road wheels?

I am thinking of buying these wheels in a couple of month time
http://www.planet-x-bikes.co.uk/i/q/WPPX52CCL/planet_x_52mm_carbon_clincher_wheelset
Intended use is race only : TTs and Crits.
They are clinchers with alloy rims and carbon fairing which I guess prevents rims from cracking when punctured.
Is there an alternative to these in the same price range? Any reason why I should not be buying these?
Any advice appreciated.

The aluminium bit is to reduce the risk of failure from a combination of hot braking surface, and high PSI racing clinchers. Both stressing the bead seat area.

If you're only going to race on them then buy tubs.

A problem already solved by this^