Any updates on which to get? I've got a Sprint Samsung Galaxy Note 3, and my wife has the Note 4. I'd like to get something where we could call each other if we get separated (going with the kids and a couple of families so coordination can be beneficial). Loading off-line maps so mobile data, while nice, isn't essential. We'll plan to use WiFi at the hotels when available.

We're flying into PEK, doing Beijing, the train to Xian, then back to Shanghai. 9 days total. I know the back and forth might put us into multiple area which won't work.

One person in the group has T-mobile. Can anyone comment on how well T-mobile's "unlimited international roaming" will likely work?

Thanks!