This report (link below) has a heavy bias, but still interesting. It doesn't answer the acceleration question, but they claim 19 watts saving between their edmonda road bike and the aero madone with a rider on it at ~40k. I'm sure it's an optimistic number, but it was enough to get me to shell out some bucks for a new madone frame after I test rode one. I've got about 2 weeks of riding on it. I won't speculate on the aero benefit (all new bikes are faster), but it's a great bike even if you ignore the aero factor. I've raced it a couple times and had it out on a couple fast group rides and it's just a fantastic riding bike.
http://brimages.bikeboardmedia.netdn...epaper_min.pdf