I used Pro Audio 9 until I could upgrade to Sonar 5 and get Sonar 6 as a free upgrade.
I upgraded every version since.
I can say the best upgrade to Sonar has been the X series. I saw what PA9 was, and then Sonar 8 Expanded really showed marked improvement.
But when the X series came out, I saw that CW was shedding the old in favor of the new.
I said it when Sonar Platinum came out, the Bakers have some plans. Their visions of four to five years ago are coming together.
Stay with X3e. But you will be missing out! I'm just saying.