[arm-allstar] Mobile Node Tips?

[John (WB5NFC)]

I'm ready to start on a project I've had on a side-burner for far too long: I want to build a mobile-only Allstar node for the car.

If memory serves me correctly, there have been issues reported in using ATT as a provider and some work-arounds are available. I'd love to hear from those of you who have already traveled down this path in constructing and running mobile nodes. I know I've heard several truckers who roll full-time with Allstar in the cab. What works? What doesn't? 

I have an ATT Unite Pro Hot Spot. Any advantage/disadvantage to using it (or something similar) over connection sharing from an iPhone? Is the Pi-WiFi adequate for connection (WiFi hotspo/iPhone to the Raspberry Pi)? 

I already have a "Pi-portable node" that I pulled from our motorhome before I sold it -- but it was primarily used when we were parked, not while mobile. 

Any/all suggestions appreciated. 

John / WB5NFC