I have both a Crosscheck and a KM (Oh check me out).
I love them both. The Crosscheck has been built up in every guise going from Fixed gear town bike to Monster cross, but I do find it a bit long.
The KM is my first 29er and I have to say I love it. I could never go back to a 26″. I don’t pay much attention to geometry its all about what suits, I find it quick, a lot more nimble than my old 1×1 or infact any of my 26s. I was scepticle of the high front end, but actually love it (that maybe because I am getting old).
If I had to own just one of the two it would be the KM. Its versatile in terms of what you can kit it out with, disc, cantis, racks, geas, ss, Alfine…