I see that Plus offers 99 vs. 32 tracks. Also, Plus has 2 camera capability, and 5.1 audio vs. stereo. What about HD support? Does the non-Plus version support as many HD formats and pixel sizes as the Plus version? Wat else does Plus offer?
For HD editing, you'd have to go for the "Plus" version. This also has a few other benefits (aside from the ones you already named), e.g. free MPEG-4 codec activation, VirtualDub plug-in interface, screen capture function, Audio Mastering Suite 2.0, WMVHD disc authoring and keyboard shortcut editor. There's also more software content (e.g. transitions and templates) in the "Plus" version.