Was at the Expo today, and checked it out at the Raymarine booth. Pretty nifty If you have a I Phone or Android, and even a Tab or Ipad. The associate sampled it for me on his I Phone, and it had great resolution. I think for $199 it's not a bad deal. Maybe a great product for Kayakers or Canoers, and the ilk.

The Vexilar Sonarephone is a similar product and it works with Navionics mapping and GPS.

If be scared of ruining my device by getting it wet. The compatible devices typically aren't water friendly. Good concept on paper though although I would think it's hard to hold your device to view the sonar while fishing unless you have some sort of separate mount for it.

The Sonarphone comes with an arm band to hold a smartphone.