Woohoo!
I am now officially a Cubase user - I went ahead and purchased the crossgrade from Sweetwater. An early Christmas for me!
I’m finding that the major differences that need getting used-to are UI/mouse clicks and stuff. Sonar was firmly wedded to the windows platform and thus had a rather consistent conventions, where Cubase seems a bit different. This isn’t something that muscle memory won’t quickly conquer though. I’m really impressed with Cubase’s capabilities. I really like the control room - it solves a lot of monitoring issues that Sonar was lacking.
I’ll continue to post my observations as an Sonar user transitioning to Cubase.