Both. Plugged into your computer, you have to run VZAccess. Plugged into your router, you don't. I have one and it works great. I use it at home with a CradlePoint MBR1000 router as a failback to my Charter cable. In the car, I use it with a CradlePoint CTR350 travel router. I don't like the USB760 sticking out the side of my laptop and I don't like running VZAccess. It works really well.
I bought my routers here http://moremobileinternet.com/