Any cellular-based device is dependent on
- Signal strength
- Tower congestion/assigned bandwidth
- Every carrier licenses a specified amount of bandwidth on each antenna sector, which can differ with the same tower but different direction. So even if you have "great signal," if a tower is overwhelmed with a thousands of users connected to it during a large event like a concert, parade, protest, etc. nothing will help you. In Canada, Industry Canada (US has the FCC) publishes a technical list of licensed antenna locations including bandwidth allocation - the data helps when pre-planning live hits.
FWIW, every 5Mhz spectrum can handle ~200 users. So finding areas or being aware of which tower you're connected to with 10 or 20Mhz bandwidth is helpful.
- Backhaul
- Data aggregated from all the antennas on the tower is sent down a backhaul to the carrier. This could be a direct 1Gig fiber or multiple microwave hops in rural areas. And your overall throughput is also dependent on how congested the backhaul is.
The government does have a very limited amount of "commandeering" of cellular spectrum. In Canada, it's limited to a very small circle of critical decision makers and law enforcement. Even then it's only valid for voice calls, users are screened, authorized and pay a subscription fee - and only then, if you require priority access, dial a special prefix before the phone number in order to use the service.
All these factors are beyond our control. It really comes down to which carrier your company prefers vs their reliability in your specific location. Then which device they believe is best.
And as far as I'm aware, none of the current 'solutions' allow for data connectivity through their bonded service, only video? It's limiting as I'm sure most of us usually send our stories via file transfer.