Some scientific research basically says it makes some difference, though that assumes that you're a pro racer.
But -- if an aero bike gains, oh, 2% in terms of wattage need of the system at 40km/h (so 25 mph)...then presumably it would gain something close to that if the "system" also included a somewhat more portly engine. So maybe 1%. So at the same effort, you'd be going 20.2 mph, instead of 20. Maybe. So, practically, no.
Now the old addage is true -- the bike you want to ride is the right bike for you. So if it floats your boat, then why the heck not.
Does not float mine. I like metal. And round tubes and personality. I would also be driven nuts by all that proprietary stuff. Saw a Venge and a Cippolini in the LBS the other day. I don't even think you can change brake pads on those things without ordering special everything. G#d forbid you want to move your saddle.
Last edited by adrien; 08-02-15 at 10:29 AM.