Picked up a 4G Mifi this weekend and at office in Champaign (where there is 4G LTE) I'm getting just shy of 15Mbps down and just shy of 10Mbps up. I have to say I wouldn't have believed it before. Sweet.
It's been spotty in other areas. Sitting at O'Hare airport it was terrible. South of Boston it was ok, but somewhat intermittent. It's doing pretty nicely here in Salem, Ma now at 5Mbps down and 2Mbps up with two of us using it. The DNS isn't the best, though. Most times going to a new site it fails to resolve until I refresh the browser.