I have an extensive collection of the Heavy Gear 2nd Edition books. I am only missing 2 books. I was disappointed to see them go to a 3rd Edition, mostly because these books are $10-$15 more expensive than the average book.
As for the 3rd Edition and dual-statting. I really don't care. The group I play with is another issue, they love d20. They also like the ability to play games that are non-d20. With the combination they have the oppurtunity to play either way or make house rules. (We usually can come to a understanding on house rules).
As for DP9, the only stuff I have is Heavy Gear. I have looked over the other settings and they look interesting. The one thing I enjoy most about Heavy Gear is the artwork. It is great, it looks like it came from an anime movie.
As for the dual statting. I know of a few settings that are coming out that are going to be dual-statted. But at the same time I know a few settings that are coming out that have said no to d20/dual-statting or are dropping the dual-stat system.