Well, I finished installation of the Humminbird Helix 10 Mega on Friday. Yesterday, the weather was perfect, so, I tested it out on Skiatook Lake in Oklahoma.
The Good: This technology absolutely knocked my socks off. One caveat, this is my first fish finder and so it's probably easy to impress me. I literally couldn't believe the unit could deliver such good imaging, so, I drove over the boat ramp at Black Dog park to prove it to myself. Also, I'm glad I didn't go any smaller than a 10 inch screen. Size matters A LOT with side imaging. I'm already devising ways to mount the head unit closer to my face. Finally, I was worried I wouldn't be able to go fast enough for the side imaging to be effective. It turns out, I was getting fantastic shots at speeds as slow as 1mph.
The Bad: I mounted the transducer below the kayak just aft of the center. While this produced good shots, I was VERY uneasy about hitting something with the transducer. Forgive the crudeness of the mount itself (see picture), this was just something quick I threw together. I'm still working on a more permanent mounting solution. I'm brain storming ways to mount it off the back of the kayak so it's not at the lowest overall point on the yak.
Anyway, thanks for the input along the way. Here are some screenshots I took.