I saw a new 1590 at a tree trade show in Boston about a week or so. It is a nice looking machine. I just demoed a Woodsman 15x. You should read my post on it. I was very impressed and I bet you would be to. Try one out.
I run the 1290, its a great machine. I think the only difference in the 1290 and the 1590 is horsepower and a larger throat opening. They both have a 37 inch drum.