AT&T vs International Lumia 920 (Which one to get)

[sinlessearth]

I need some help with a decision. Right now I am in Germany and use T-Mobile (Deutsche Telekom) here. I will be in Germany for another 3 years then heading back to the US where most likely I will choose T-Mobile US again because I do not like AT&T customer service or their crazy plan rates. Verizon and Sprint are not an option because I don?t care for CDMA as it is not used around the world. So I looked at Nokia.com and Nokia Germany to compare the specs for the AT&T vs the International version and noticed the big difference is the AT&T lacks WCDMA Band IV 1700, LTE 800, 850, 900, 1800, 1900, 2600 Freqs. I can buy the AT&T off contract for like $449 but then AT&T will charge to unlock it (Does anyone know the price of this?) or buy the international version (unlocked and unbranded) for about $650 or so. Will the international version work on T-Mobile back in the states because it has the 1700? What would you all do? Just looking for some opinions on this.