I've had my Diverge for 3 weeks now, probably 250 miles, 80% on road, rest on packed dirt. Has 38's for tires and they're mostly designed for trails, not roads. Still, it rolls well and is close to my Robaix in performance and geometry is similar. I've no doubt that if I put slick 32's on it , then it would be a pretty good road bike. Flats and downhills are close in performance now, uphills a bit slower. Future shock is a bit weird on roads as sometimes you want a stiff front end and it gives a bit and which can be a little bothersome while climbing a paved road. I'm happy though as it makes riding on chip seal so comfortable and the off road stuff is the best. I'm no racer but it seems to hold a line through curves well, maybe I'm just more confident in thru axles and wider tires do help. Brakes are great also and give confidence.
It really is a sweet ride and is the closest I've found to be a perfect all around bike, at least for me.