iirc, the Razha K is the replacement for the FP Due. I think the geometry is close, but don't remember for sure. The FP Due was a nice bike and the LBS where I work sold a lot of them in 2012 and 2013. Decent frame, mostly 105 or Rival kit depending on the year.

Fatandslow, thanks for your thoughts

Not answering your question but I'm in the same boat as you - currently doing my riding on an aero road bike, and want to add an endurance road bike to the stable. Didn't consider the Pinarello, but considered the Roubaix, the Domane and the Bianchi Infinito CV. Very much leaning towards the Bianchi with Di2.

Razha doesn't have the slack head angle of the others. Colnago CX-Zero might be a better choice if you want Italian (though cost could be an issue as it's a lot more expensive)

Cyclenutnz, thats a lot of great info, thank you for putting it together. Love the Colnago, but unfortunately out of my price range.

The Colnago AC-R has fairly similar geo to the CX-zero in that size. Fits the same as the Roubaix but a lot more stylish.
If you need a bigger size the AC-R goes to a more normal road geo so it's just in the small-mid sizes that it's like the endurance models.