[aiharkness]

@jasonnet Your profile says 8100 and your post says Q10. I'm assuming Q10 and you didn't update your profile. So, here's the deal for Q10....

BlackBerry 10 models do not use BIS. You should be, and probably are, operating on a regular AT&T mobile data plan instead of the BIS account you had on your line with your old device. Consequently you shouldn't have any issues using another SIM on another network, provided you have mobile data on the SIM.

I say shouldn't. I haven't done it. One thing I might anticipate is having to re-validate email accounts. If you have two-factor authentication enabled that could be a hassle, but not insurmountable. All the other data services, BBM, browser, Maps, etc. should not skip a beat.

Please post an update and tell us how it goes.