there have never been any real gameplay differences between versions of the same set (i.e. red/blue, gold/silver, ruby/saphire, etc.), except that the third has always been "special" (yellow had only pikachu as the starter, and he followed you around, crystal had a garuantee to getting suicune and the battle tower, etc.). The biggest differences are the availability of certain pokemon, forcing you to trade with paople weho have the other version in order to cath 'em all.
That said, i will get black or white eventually, however, i have barely gotten through soulsilver, and i often find the battle system tedious because of the times it takes for things to happen. even when messages and battle messages are set to fast.