Though there are more significant differences in the controls than this, the focus-selection switch illustrates the level of detail to which the companies went to differentiate the two cameras.
In addition to each company's color-coding scheme, Samsung and Pentax use different grip material for the lens rings. I find Pentax's rings a mite grippier than Samsung's.
It's no illusion--Pentax uses larger text and provides generally bigger controls throughout the camera than Samsung does. I do find the GX-10's metering selector easier to manipulate, though.
All of the controls on the back of the Samsung are smaller and flatter than those of the Pentax. Aesthetically it's a bit more pleasing, but ergonomically they're not as comfortable to use. They also feel cheaper and less solidly designed.