I road my new Enve aero bar for the first time last night. I absolutely love it. I didn't tape the flat part and it was extremely comfortable, both from a hand position and less road noise due to the absorption of the flat bar. As they tell you the bars are narrower than the the numbers indicate and they are but I, personally, thought my old 44cm Enve road bar was a little too wide so I love the narrower width (tagged 44cm, also). I am 6'2 but don't have that broad of shoulders. The narrower width also made it more comfortable "down" on the drops. My legs felt good last night so I can't say it made me faster but the whole experience with the new bars was fantastic! I will be riding 80-100 in WI this weekend so I will follow up with a report from that ride where we will climb around 5000'.
As a side note, I had ordered the "old" Enve Aero bar, hadn't received it yet, and the new Enve Aero bar came out. I took deliver of the "old" bar, liked it, but thought the markings on the top of the flat bar would wear and look bad after a while so I shipped back those bars and ordered the "new" Enve Aero bars. Very happy!