Call quality was average with some minor hissing heard on my end of the call. When I tried to hang up, the proximity sensor did not respond and so I was unable to end my call. I had to pop open both screens (activating the speakerphone) in order to hit the "End Call" button. This happened both times I tried making a call.

The Echo also cannot take advantage of Sprint's 4G WiMAX network, relying instead on the CDMA network for voice and data service. This might ease the burden on the phone's battery, but other services might sap the battery just the same. While I couldn't run exhaustive tests on the battery, I noted that having both screens open and running seems to eat away at the battery rather quickly--the battery dropped from 30% of capacity down to 12% in a span of 30 minutes or so. Kyocera may have anticipated this; it includes an external battery charger with the phone. Echo users might do well to pick up a spare battery and carry the charger at all times.

Software

The Echo comes with a largely unmodified version of (Froyo) with relatively few add-ons.

It comes loaded with a handful of apps that can be run simultaneously using both screens. "Simul-task Applications" (as they are called) can be identified by a small blue square that displays next to the application icon. To run two applications at once you simply tap both screens at the same time while running a "Simul-task" app. A list of compatible apps will pop up on both screens, and you can choose which app you would like to run alongside the one that is currently open.