Audio Systems: Bose sound system, bose 321 gs, bose 321 system

Question
What is the difference between the Bose 321 GS II system and the Bose 321 system?  

Answer
The Bose 321 GSII is just the "next generation" of the prior version of the 321 system.
There is also now a "GSX" version with a hard-disk digital music recorder/player.

I am afraid that I am not allowed to go into the exact specifics of design differences between the two generations.

I would not endorse any of the three personally, though that doesn't mean that they aren't perfect for you.