Check the nextel broadband web site to see that their service is tier'd and to get 1.5 mb service, the cost is not competitive with cable. the cable competitive price point only provides for 750kb down/215 up.
Who gives a rats behind? I'd pay $50/mo for 750d/215u.. being able to use it on the road makes up the difference. Sprints 144kbps service would be tossed in a heartbeat.