Using a Cellular only connection

I have a CradlePoint MBR-1200 that has served me well for more than 10 years. I also hear PepWave works well with data cards and tethering to cellular data networks. In my CradlePoint I have used Verizon, Sprint and AT&T devices and networks. The actual manufacturers of the data cards are Sierra Wireless, Pantech.
I was about to buy an Asus RT-AC3100 which also supports 3G/4G USB data cards but I keep waffling on if I should wait for next gen. Another problem keeping me from spending so much on one of the new cellular capable routers is the fact that Comcast may finally be an option for me.

I use a Netgear LB2120 on a Verizon. Works great.