This is probably common knowledge but I thought I would share anyways.
I just recently switched from T-mobile from AT&T and called to inquire about T-Mobile Cellspot routers.
If your request it, T-Mobile will ship you a T-Mo branded Asus AC68U router at no cost.
Cheap way to get a very nice AC band router on a budget if you don't have the $$$$$.
The cons:
-The router remains t-mobile property so if you end your service you must return it.
-Custom T-mo Firmware, although flashing custom rom does not break the terms I have not tried it.
-If you flash a custom rom and break it , are burgled, or your house burns down while being swept away in a hurricane you are responsible for the cost to replace the device.
So I looked at the manual and you can turn it into a access point so it should work with a pfsense box. The interface looks like the basic Asus skinned DDWRT that all their routers have.
I was going to buy an AC router but now I am going getting this for fucking free.
I should also add, instead of a Router you can request a Nextivity 4g signal booster (retail $575.00USD)
I'm not familiar with these, but it looks like some type of signal amplifier and repeater that consists of two components a "network" unit and "coverage" unit. It states you must have at least "1 bar of LTE" coverage where you are trying to use it and is only recommended when a broadband connection is not available as the router is a better solution.
On the unit I got, the firmware was a indeed custom version of the Asus firmware. It had no dual wan support , asus download manager, and you could not disable QoS VoiP priority (the t-mobile WiFi calling feature).
I was able to flash the router back to stock Asus firmware using the asus recovery utility.
However I would not recommend doing this unless you are confident recovering hardware. Due to the chance of bricking the router and being liable for the replacement cost.