This Aero-bar is my first one, so I can only compare it to the Carbo Stryke on my Dual. It won against that one. I removed the Carboy Stryke and attached the Easton.
After buying it I attached the clip-on on my road bike. Aero position was not too great, but I liked the armpads already. The length of the extension fits me well and is available in three sizes. You can't adjust anything apart from the armpads. You can narrow or widen them but that's it. My ellbows lie in the pads and I have never faced trouble with moving ellbows or sliping in the pads. There are small air channels, but I guess they are just placebos.
After buying the Dual I tried to adjust the Carbo Stryke. It ended in absolute unhappines. So I got it ripped off and attached the Easton clip-on. A great decision.

But have in mind, if you don't like it at first use, you never will.
It is prepared for internal cable routing.

(Please excuse spelling mistakes: I am german and not a native speaker)