I would not hesitate to recommend Verizon’s 4G LTE network. It’s head-and-shoulders above Clear/Sprint WiMAX and will likely stay that way for a while thanks to their use of the 700MHz band. Verizon’s rapid network expansion and broad 3G network are reassuring enough to entice me into a 2-year contract. And the Novatel MiFi 4510l is a fairly solid device, though not perfect.
I love my Cradlepoint PHS300 router. It’s been a constant companion for me for two years, providing Internet access for me and my friends at just about every conference I attend (and organize!) It’s a battery-powered box with a USB port and WiFi radio. Attach almost any 3G or 4G modem or smartphone (other than the iPhone) and you’re online and sharing. And it’s better than a MiFi: You can customize the experience, it’s faster (in my testing), and it scales to support way more users.