which is better usb or mifi

I have the Verizon version of the MiFi it's called "Jetpack" It a 4G device that can support 10 device on 4G and 5 devices on 3G. I don't have any experience with the USB device (UML290) and a separate router. But I can say the Jetpack is certainly more portable. I use mine in the car on trip, at family reunions, various events (like my son's tennis matches). It's great because it's small, I've had the Jetpack in my pocket while I sit on the bleachers using my WiFi only iPad. I get really good reception with it in all the areas I have been. Sometime simpler just might be better. There is also an external antenna you can use, I have it but I've never used it.

Hope this helps..
-Pat