Signal strength is marginal where I live but EVDO is the only game in town. I use a 3G Sprint Aircard 597E with a 3 watt amplifier and external antenna on the roof, provided by evdoinfo.com. I get about 1.1mbps down and upload is fast enough that I don't think about it. Ping time to yahoo.com this evening is 79ms.
I've also installed broadband wireless routers with EVDO card, amplifier and antenna pre-configured by evdoinfo,com for friends in the area. Never a complaint from Sprint or Verizon, and my friends are delighted.
I've noticed that the routers establish a rock solid connection, whereas my Aircard 597E requires "Sierra Wireless Watcher LIte" software to "activate" the card. The Sierrra software crashes about 20 times a day and I am among the many who absolutely detest the software. Somewhere there is a Sierra QC engineer who did not put this on his resume.
I've had the contract for a couple of years; for $60/month I download >1 GB/day with no surcharge or complaint from Sprint. YMMV.