I myself would like to try Sonar Platinum before committing to the upgrade and giving them anymore of my money.
I've been using Sonar for a while now and I like it - but now, I'm not sure why... I've recently started feeling uncomfortable with using Sonar and a few little issues are becoming an annoyance. And I hate seeing new features on a DAW such as Sonar while there are still so many bugs and basic functions that seems to be left-out when these new versions come out.