I've never ridden an LC4 400, but my friend took a demo ride on the RXC (the dual sport version) 400, around '97 or so. It is a tall, relatively heavy motorcycle with a linkage suspension that shares very little with the new 4 strokes. Overall, he liked the bike and thought it would be good platform for a dual sport, but it is not in the same league as the newer KTM 4 strokes if you are looking for a race or trail weapon.
Still, if you are not happy with the TTR, it might be an excellent trade for you.