Here is a way to switch between a remotely shared screen and a local machine without losing the newly added remote control with Command keys, specifically, Command-Tab.
I just finished reading a post on how to bypass (and users weighing in on) the new Screen Sharing feature where commands are passed to the remote machine. I'm split; I do like the increased control over the remote machine with one exception: switching applications, specifically back to the Finder. Command-Tab is now sent to the remote machine, but that is how I used to switch from the shared screen to my local machine. I want both; remote commands but local switching.
My first solution works because my remote machines are desktops, and my local machine is usually my laptop. This allows me to use the four finger swipe which is ignored by the remote machine.
But then I hit on this solution: Spaces. As far as I can determine, Spaces commands are always local. So I assigned Screen Sharing to Space 2 and use whichever key command I've set to go back to 1, which has the Finder and everything else. Voila, fast switching between remote and local without giving up the new remote command keys. Plus, having the shared screen on a different Space clarifies which machine you are working on; remote or local.
I also set my remote machine to grayscale for faster refresh and clarity. This can be done using this command in Terminal on the remote computer:
defaults write com.apple.ScreenSharing controlObserveQuality 2
[crarko adds: This hint talks more about adjusting the remote machine's display depth.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=2010081616121830