Not worth it my opinion. I switched to a compact carbon crank (50/34) just before the Triple Bypass in Colorado. I kept my Dura Ace front derailleur (lowered by 1/2 inch on the seat tube) and it shifted fine between the climbs and descents (and minor flat spots on occassion).

It's just a marketing ploy...stay away from the evil marketiong folks in cycling!!! Remember, they are also the ones who want their components weight in bright BOLD numbers and letters (while being weighed on the 3rd moon of Jupiter to shave an extra few grams....).