What'd the difference between the Hercules and a normal Galaxy S2?

After seeing a bunch of tech. demos of the Galaxy S2 online ich really want this phone...I was thinking about ordering an unlocked phone off ebay from a guy in Europe because I have the cash now and don't want to wait till the end of October for T-mobile to get off it's @ss. I was talking to some guys at school about it and they told me to wait because the American relese will have different tech. specs. and they said something about US carriers using different bands and European phones not getting good transfer raits over here.... anyone know what he was talking about? I need a new Galaxy / Hercules / whatever its going to be called but I don't want to shoot myself in the foot. Can anyone help me out?

What's the point of that? If its the samephone why don't they just keep the name? I wasted like an hour trying to find out the exact differences... I want my time back!