Where I saw the most lag/stuttering in my tests was clicking the full-screen button in 'iPhoto'. Didn't see you try switching in/out of full-screen apps in your vid.
I did show Launchpad, MC and Expose in that video. All with no stuttering. Some stuttering with two 1080p videos open, but that was fixed when I enabled the 650M. I was asking the other guy what applications he wanted me to show the minimize animation with.
No, the other posters are not liars. They may very well have had a different experience from you. Like I said, not everything in this world is black and white. Especially in a non-ideal world as you described, actually.
If you genuinely believe that everyone other than you is wrong, you should take a step back and reexamine yourself. You won't get very far in life with that kind of mentality.
All Macs purchased after WWDC are going to get Mountain Lion free of charge- just download it off the App Store when it's released.