Two years ago I did broadband drive testing with a trunk-mounted Netcomm unit and was able to keep data at megabits per second in places my phone had no signal at all.
I have a fair number of Robustel R3000 units deployed at remote sites for SCADA, OOB network management, and weather monitoring:
In the case of the Netcomm units they're on a virtual private APN, and I push a /24 of my own 1918 address space to each. And the dual-SIM thing really works, and can be a lifesaver.
I also have a pair of Mikrotiks with the Sierra LTE mini-pcie card as sold by Go Wifi, they seem to work but I have not deployed them yet so I can't recommend.