My guess is WiFi only users will get it first, followed by 4G then finally us schleps who never upgraded will get it last. At least thats what seemed to happen last time.
But you know what, I'm OK with that. I just got my ICS a few weeks ago and I'm enjoying that - since Jelly Bean is a .1 release I'm not expecting anything earth shatteringly different so I will just be happy to take it when it comes.
I, for one, an just happy that our 1 year old+ tablet is still seemingly in the minds of MotoGoogle and hasn't been left on the shelf to rot.
It's been nice this last year to see the Xoom constantly feature in Consumer Reports top tablets section, still fighting hard against the ISad...
If I helped you then please consider thanking me. A thanks produces lots of warm and fuzzies and is cheaper and easier than buying me a round of booze.