It's funny, while I really like the looks of the 250/400Ts (hated the Ns with those silly guards), I'm not sure I ever liked them. I have recently owned both a 400N and a 250T. I didn't like the forks on either (and I had 400N forks on my HL500 where they were even worse), don't like the sidecover bulge, and found the power of the 400 very mild. So my experiences seem quite different to everyone else's.
That said, they are great handlers and I think the 400 was the best vintage bike I've ever ridden at flat track, even if it was too slow.
Of course this all may say more about my riding ability and setup skills, but still...