Nebula is known to be quite a resource hog. I don't use that shit. I have huge sessions going all the time with tons of plug-ins no problem on my quad-core i7 iMac with 4GB RAM. The Slate TRIGGER crashing the DAW on close can be avoided by saving the project, then doing File>New Project, choose an Empty project template, choose whatever folder it's not important, click OK, when the new empty session opens up, then Quit Cubase. Should Quit without any problems. I don't know why it does it, but I know a ton of people have that issue with TRIGGER. Also have no idea what you mean about OSX's responsiveness, OSX has been way better for me than Windows ever was when it comes to that, I'm on OSX 10.6.8.