I have more than 500 miles with the handlebar as I write the review. I installed it myself for a mechanical Ultegra R8000 set. There are holes for internal routing which I didnt use because I wanted to use my old cable housing, so I just taped it before wrapping the bar.
I didnt wrap the Aero flat portion and it looks gorgeous. Very comfortable and light, highly recommend it.
I found the EC90 to be very comfortable in the drops in my very aggressive set up.