I have an old iNet6416 and it has the same Soc of the GL-MiFi, and I thought to upgrade to the Slate with external LTE modem. But I may wait for a new MiFi.
I like the convenience of powering the router with a USB cable, without carrying a 12v power supply. USB-C can provide more power (up to 15W on 5V), possibly increasing the SoC specs.