You will love the Cannondale if you're on single tracks a lot. You will love it a bit less if you are more into long stretches of gravel due to it's directness, and when buying a new wheelset or want to upgrade to a powermeter enabled crank. Due to the AI offset (https://cannondale.zendesk.com/hc/en-us/articles/219101107-Ai-Asymmetric-Integration-) of the back wheel all new wheelsets will need to be re-dished, and you will need a 6mm longer axle for your crankset = MTB width.
I gotta disagree with how he'll like the SuperX on long stretches of gravel. With a 71 degree HT angle and 422mm rear stays this bike is very stable on straights and descents. It really shines on that terrain. Just have to have a decent tire width and low enough pressure with tubeless. I agree upgrading parts was a bit more costly: I had to dish out $90 for a bigger direct mount chainring and I'd love a 2nd wheelset but forgot they would have to be re-dished for the AI offset (another cost). It was easy enough to find a used Stages left crank-arm on eBay for adding a powermeter.