I have only had this unit out once on my kayak but I love it. I considered this unit (597ci HD DI), the 788, 798 and the comparable Lowrance units for use in my kayak. I decided that I did not want to pay the premium for side imaging, and wanted a traditional sonar as well as DI capability. I also decided that I wanted as many pixels as possible on the screen for sharpness. In the end I felt that for me this unit offered the best tradeoff in cost, performance and features. I was also fortunate to catch it discounted on Amazon for $567.99 (with overnight shipping). At that price the step up to the 788ci HD DI was not worth it for me (another $160 for a better base map and dual SD slots).
I installed the transducer to shoot through the hull of my kayak. The performance shooting through the hull seemed great. However, I don't have a comparison with not shooting through the hull. In the end I had great pictures in 135' of water. I was happy
I was impressed with how readable the screen was throughout the entire day. I had clouds and sun, but never any problem reading the screen from about 4' away.
The 2D sonar was really great at both the 200kHz and 455kHz settings. I anchored in a channel near the edge of a canyon like rise from 90' to 60' to see if I could the difference in switching between the two transducers. The wider 200kHz was picking up the 60' edge of the channel while with the narrower 455kHz I only saw the 90' channel bottom. It was cool to see the difference. I think this will be useful when trying to precisely anchor in these situations. I marked many fish throughout the day, however, I can not be sure if they were real, junk in the water, or artifacts. I need to run some tests in some really clear water some day.
The DI capability was impressive. I fished over a lot of rocks and boulders and they showed up very clearly. There were no trees or weeds in the area I was fishing so I did not get to match a real world view that was similar to those on the simulator. However, the rocks show up with incredible detail. I used the sonar in split sonar/DI mode a lot of the day and would sometimes switch to whole screen for the sonar or the DI.
The GPS seemed pretty amazing. I went back to a spot (near the shoreline) that I had marked early in the day and it put me precisely back on that spot. I was impressed. Way better than my 20 year old GPS used to do! Once I got back home it was also very cool to be able to download the waypoints and plot them on google earth using HumminbirdPC. They showed up exactly where I marked them (relative to the docks).
There are a ton of features I have not explored yet, but so far I am really happy with my purchase. I can only imagine liking it more and more.
Fish tremble when they hear my name
A ship in harbor is safe -- but that is not what ships are built for.
--John A. Shedd, Salt from My Attic, 1928