That 100 is a pretty nice rig for lots of things. where i am they resell really well. I sold one to a man who was on the height challenged side (miniature Arnold) who rode it unitl he bought a new one just like it. If you are trail riding and you want to keep low maintenance and easy to ride in the forefront, look at the kdx 200/220's. the 250's if you get an unthrashed one are always a good step up, but if you dont have others who are experienced to ride with and kind of mentor you along with setup and technique you may want to consider something more trail oriented like the kdx's. that xc-f listed above would be a good ride, but expect to pay about twice what you would for an exceptional kdx. ditto the wr yamaha and crfx hondas. if you go fourstroke 250 i would avoid the early versions of the kaw and suzuki.