My nephew Mike had one and my great nephew has the 390. Both like them very much. I rode Mike's. It was very tall lol.
I had one of the original 690 Dukes (08 or 09 I think). It was an awesome bike and did great at the track. My next bike is going to be the 790 Duke when they come out next month.
A friend of mine has a 690 Duke and loves it , he is small but can handle the bike well.