I had the same idea - it seemed like a good idea at the time, but I am now looking at dropping the MiFi. Notwithstanding the premium price/GB vs. a 3G plan, I didn't find the Mifi to be particularly reliable - frequent lockups, drop offs, short battery life. I've had to replace the device twice now..
I wouldn't recommend it for business use.
I wouldn't recommend it for business use.