I, obviously, cannot use the Upgrade for the B2 => Vibrant. I think we ALL know this.
However, I COULD
A: Use the second phone on my account (the one I gave to my mother for emergencies) as an upgrade... There's NO way should could EVER POSSIBLY understand how to use a Smart Phone ;->
B: Do as above and "convince" T-Mobile to send me the Vibrant
C: Get it through work (They always end up with my "cast off" phones anyway, and semi-subsidize my personal phones, and as they're on T-Mobile, the Razr V3 they have is MORE than able to use the Upgrade)
D: Just wait until there's a REALLY GOOD reason to upgrade (Hardware 3D, 2Ghz processors, HTC 1 stops being a prototype....)
So far, I'm sticking with D. The B2 is flawed, but it's hardly "unusable".