Any differences other than weight? The guy at the local bike shop said the main advantage of the carbon is the 'feel' when pedaling. Can you really feel any difference? I will be using them with Sidi Genius 5 shoes on a mainly carbon bike (including carbon cranks). I will probably end up with carbon due to 'cool' factor, but just curious if there is any truth that carbon pedals would 'feel' better. Thanks!