Kind of an old thread here, but this is my experience with KTM. My 05 450 had 227 hours before I had it rebuilt and I saw one on the internet that had 100 more. They both looked identical in wear. I was the second owner of mine. I hardly ever adjusted the valves, since I've owned it, and with the stainless valves, it'll be a lot less. There are two things that bug me about that bike. First, it's the forks. They need to be re-valved, I'll have to do it on the next seal job. The second thing is the shifting. It works, but not as good as Honda. My CR250, like most Honda's shifted like a dream. I don't think anyone can beat theirs.
We also have an 07 85SX. If you ride woods, I highly suggest this bike. It is a torque monster, for an 85 and is much more fun and easier to ride that the japanese hard hitters. I cannot stand pushing my sons friends CR85 up a snotty or rocky hill. You have to rev it to the moon and try, try, try not to break traction.
As far as parts go, KTM has that all figured out. The same shifter, seal, gasket, whatever, will fit many different bikes. Because of that, my local dealer usually have what I need. Try that with your japanese bike. While we are lucky to have a good Kawa/Yama dealer here in town, who does what they can to stock your typical parts, our Honda dealer stinks.
We still have one Kawa KX250. It's a great bike, but it's a 2000 and will need to be replaced soon. I'm sure we'll be shopping KTM's first and it'll be a 2 stroke most likely, 250 or 300. As far as prices go, I'm not rich. It is not a rich mans bike any more. Also, the replacement parts, in my opinion are very, very reasonably priced. Plus, Enduro Engineering has loads of parts that fit them all. How many different seats can you buy for your CR250? One, maybe two, maybe just a cover change and have a local shop skin your foam or something. I can get at least 4 (I think 6) different seats for my EXC.