I have the Sprint AirCard 595U. it works fine. you do not need a router for mega$$$$ or the booster antenna for more than $200.
Aircards work as follows;
It will work from approx. 72kb to 960kb transfer rate anywhere you can use your cell phone. it will work at 1meg to 1.5 meg only when you are near a repeater station which has additional equipmemt on it specific for High Speed DSL. these to date are only installed in a few major cities. more comming. unless you intend to "LIVE" on the internet and upload and download files all day - no booster and no router.