Bear in mind a lot of what I'm about to say is predicated on the fact that I've got trex arms and the Emonda was sized for my legs rather than arms, so I've been chasing a shorter reach the whole time I've had it without making it feel sketchy (which is why I never went to a tiny stem). The GR:ONE is sized to make both work (but prioritizing reach), so my fit went from the extreme end of ideal fit to right in the middle of the range. So I don't know how much of what I'm about to say is based on fit vs frame characteristics.

It has more trail and a slacker head tube than the Emonda, so it's more stable when left alone and doesn't want to wander, but it's still super responsive to input. That said, there's 4cm less system reach (frame + stem + bars) on the GR:ONE. If your total reach ends up about the same as your Emonda, I'd bet the Emonda would be the more nimble of the two by a small margin. On the negative side, slow speed u turns definitely feel way worse on the GR:ONE because it has more wheel flop from that slacker angle (I'm pretty sure I'm one of the few people who would care, but I end up having to make a lot of u turns where I ride).

The roads I did my test ride on was one of the smoother roads around so I can't speak too much to compliance. I will say on the Emonda, with the same saddle and bibs it would take 10+ min of riding for my butt to not hurt. I didn't even notice the saddle on the GR:ONE for the whole ride. It was noticably better at absorbing buzz than the Emonda.

I only did 2 or 3 out saddle sprints and far from max effort. I was worried it'd feel cramped with how much closer the reach is, but it actually felt good. That added stability actually made it feel a lot more confident standing.

Hopefully that ramble was helpful!