No, I've never ridden a MX track. Both my KX250 and RM125 are down right now. I should have my RM up within a month, and I haven't opened up the KX yet to see what I damaged at my last dune outing.
The RM ran excellent when I took it a part. I'm doing the top end as preventive maintenance. It will be my introduction to MX. My KX is set up for woods.