I swapped out my 54cm 2012 croix de fer frameset for a 55cm Kinesis Tripster ATR (which seems pretty much exactly the same cockpit size) and saved nearly 2.5 lbs, some of which will be going from the steel fork to a carbon one.
However my croix was only 22.5 lbs anyway so I the weight saving isn’t hugely noticeable.
The tripster is also slightly slacker than the older 2012 croix, and once I had built it I immediately missed the quicker steering of the croix.
The new croix is also supposed to be slacker, so if you like your current croix I would check that you also like the new one before swapping over, as it will become more sedate and not as much ‘fun’.
With the tripster I have gained much fatter tyre capability with mudguards (40c with 45mm guards, maybe bigger with 50mm guards which someone has fitted – going to try 42c this weekend) and a lot of bump compliance in the frame, which is what I was after, but whether the new croix offers the same scale of benefits over the old one is another matter.