FreedomPop is now officially expanding to include Sprint's 3G network, effectively "guaranteeing full nationwide coverage across the US." This is far better than the 4G-only service that it had up until now, because it means that you can fall back to the 3G network where 4G isn't available. And yes, you can still take advantage of the 500MB of free data each month, plus rollover data and monthly upgrades. The new device is called the FreedomPop Overdrive Pro and it's a 4G/3G MiFi hotspot.
When I spoke with FreedomPop earlier this year about their expansion plans, they said that they really were just waiting for Sprint. In this way, they're not quite ready to do the nationwide 4G LTE thing just yet (that'll happen "later this year in line with Sprint's nationwide build-out"), but at least we've got the 3G fallback now.
Head over to the order page to get your hands on the Overdrive Pro while supplies last. It's going to be pretty popular!