Somewhere I thought I read that the EX1R allows you to program a user programmable button to mark a clip as 'good' in camera mode instead of switching over to playback mode to do this.

Is this true? I couldn't find any documentation anywhere.

This would be very handy to note good takes when filming line delivery type stuff, etc.

shot mark 1 and shot mark 2 and OK mark are all assignable buttons.
Shot marks can be added right after a shot is completed before the next clip is started.

no shot marks can be added to SD

Clips marked with OK shot marks will not be deleted when you select delete clips stuff.
(but dont delete anything based on what i just said :-)