Well... one plugs into your computer via USB and it gets 4G through AT&T. The other one creates a hotspot, which you can connect to from your computer via wifi. If you are using multiple devices, then latter. If you know it's only ever going to be used with one device, former.
"I can drive my hummer through your loophole."-Arnold S. "Guiliani says three things in a sentence: A noun, a verb, and 9/11"-Joe Biden