I had an xsport stomp and some Chinese one, tbh I think there all shite there just for abit of fun but as I'm 6"3 they kill my hips and legs, If I was you I would start on a 125! They can take a serious amount of abuse and I like it better than the 250 because there a lot lighter and I think a lot more fun to ride and throw about, I have been to many test days and been on every make of 125 appart from tm, my favourite was and is still the ktm125 but 2007 and newer as they done a lot of changes in the frame and suspension in 2007 and there excellent bikes ! I would stay away from 250 2strokes as they will rip your arms off haha ! And 450 4strokes are heavy and if they go bang it will be expensive