Melodyne's ARA tech is now available for all DAWs, so I'm assuming it'll be in X2. S2 lacks a dedicated tempo view, and makes it nearly impossible for smooth ramps in the tempo view it does have, which I have to have for scoring. It simply makes things more realistic when I can speed my midi up the way a human would before a section changes. The tempo changes in S2 are stepped and clunky. Also, no way in S2 to build preset trees for my plugs, and I have close to 400. No desire to dig through a browser for what I need when I can build an intuitive system myself in Sonar.
That said, I do love the way S2 builds projects and the mastering tools that I comes with, and that's why it is still on my machine. Can't use it for composing, but when it comes to the finished product, it simply does the red book standard far easier than any other program I've used.