The 4G Mobile Hotspot's performance varied across a wide range in my tests, which isn't unusual since many variables--including proximity to the cell site and the amount of traffic the site is handling at any given moment--affect both Wi-Fi and mobile broadband speeds. But even the fastest download speed results I recorded (using speedtest.net) fell short of the rates of 5 to 8 megabits per second (with even higher bursts) that the company says are typical.

In one set of tests, both downloads and uploads hovered between 2 and 4 mbps; in another, I occasionally saw passes exceeding 4 mbps. The overall averages in my tests were 2.8 mbps for downloads and 2.2 mbps for uploads. Even so, the hotspot let me stream Netflix movies with almost no difficulty--though at one point during each film, the unit went to sleep for some reason, causing the film to stop.

Tests on my iPhone using the produced similar speed results (averages were 2.7 mbps for downloads and 2.6mbps for uploads), but latency on the iPhone connected via Wi-Fi to the same hotspot was more pronounced, with an average lag of 141 milliseconds versus about 71 milliseconds on my notebook PC.

Handoffs between different generations of wireless networks were a bit awkward: The unit seemed to need a few moments to fix on a 4G signal when I drove around, though I detected no disconnects. It seemed very sensitive to changes in network signal strength, however, as the number of bars varied often as I drove through coverage areas.