Advantage Pro features over Advantage:
1-silver spray painted case top
2-second memory module (you can add one to the Advantage by inserting...not soldering)
3-a tiny hidden switch to 'lock out' the programming feature, so someone can't blow out all your macros and remapping. You can solder one in for less than $5 on an Advantage if you want.
Any Contoured model comes with Cherry browns or reds.
A perk of the silver is that it doesn't show dust like black does