Keyboard shortcut for "mark as reviewed"?
 

Is there one? If not, can I assign one?

Thanks!

shift-command-R
It's in the Edit menu.

cmd-shift-R... there's a handy list of shortcuts at [url]http://www.omnigroup.com/ftp/pub/software/MacOSX/Extras/OmniFocus/OmniFocus-Shortcuts.pdf[/url] but for some reason they don't have that one listed.

You can set up your own preferred shortcuts with the Keyboard and Mouse panel in System Preferences.