I have 3 motards including a KTM 450 EXC with lowered and modded suspension, a Honda CRF 450, and an Aprilia 450 twin. Fun to haul to the track, and they are street legal so occasional runs to the hill country. Three sisters FTW!
I've not done any off roading or adventure riding, but I do some MX in my back 40 on small bikes (150Rs, TTR 125s).
Katooms are relatively high maintenance, even more so than some other brands of similar build. All the 450s require regular oil and filter changes. Rarely do I put more than about 500 miles on one without changing the O&F, and valve settings need to be closely monitored if you are constantly leaning on it, which is what they live for.