I am looking for a Kestrel in road spec, but I will do some tris with clip-on.
What about the dual position seatpost? Does it really works? Any comments ?
Assuming that you are talking about the Talon, the aluminum seatpost is a really heavy addition to a really nice bicycle, the carbon fiber one is better, but I went with a Thompson Set-back post set forward for huge weight savings. The Kestrel seatpost looks great, but I have my doubts about the advantage 6 or 7 inches of aero seatpost vs a round one. In races I always wrap my number around the seatpost so it doesn’t matter anyway.
I ahve the carbon post on mine and it functions and looks great.
It depends upon what “functions” means to you 
As mentioned, it has 2 locations, so you can use either one.
The aluminum is heavy (I have one), the carbon is better.
Do you need to get more forward? The Talon in itself is a very nice road bike, but on different forums you will hear the same story that it works for some, but those who prefer to ride a steeper geometry (including myself) just can’t seem to get forward enough without the bike getting squirly on the front end (even with a larger frame). They just aren’t made for steep riders.
So once you establish what “function” means to you, then you know whether you’ll be better off with one.