Which Lumia 900 would work best on TMO?

[fourfone]

I am contemplating getting a 900 but unsure as to which would get the highest data speeds on TMO. The three options would be:

ATT 900, which could presumably be unlocked (though not sure)
Rogers 900, out of contract price (presumably unlocked)
European/world 900, unlocked, when available, without LTE

The preferred route would be ATT, IF I can get them to a) unlock the phone and b) keep my 'current' unlimited data plan - which is still showing as a CSD / TDMA plan

Which would be better short and long-term on TMO???

[Volaris]

It's possible the 900 may not even get 3G on T-Mobile, unless you live in one of the few markets that have PCS/1900MHz 3G.

So far Nokia has confirmed it supports AWS for LTE, which both Rogers and AT&T use, and T-Mobile has said they will eventually launch. Listed supported bands on Nokia's site:

Operating Frequency

Operating band

GSM 850
GSM 900
GSM 1800
GSM 1900
WCDMA Band V 850
WCDMA Band VIII 900
WCDMA Band II 1900
LTE Band 17 (700)
LTE Band 4 (1700/2100)

[fourfone]

So basically, the 900 will be a 2G/Edge phone on TMO until they launch AWS LTE . . . in my market. Does the World version 900 support TMobile's 3G/4G AWS frequencies?