They work well- I've got no complaints about them.
Having used alloy pedals and the corresponding carbon pedals for 5700, 7800, 6700, 6800, & 9000... there aren't enough functional differences between them to bother with.
Not a common problem for track pedals, but on the off chance- I'd probably stay away from the Dura Ace ones- the needle bearings are more of a pain to rebuild than Ultegra or 105.