I love gadgets, I love electronics, I love fishing. So, my vote for the World’s Best Fish Finder is:
Two Old Guys in a Lund
I don’t care how much you pay for your GPS/Sonar/Fish Finder, it will never beat the fish finding ability of two old guys in their Lund. I have fished on brand new boats, with all the toys, and caught a lot of fish. Get back to the dock at the end of the evening and the two old guys in the Lund, usually a 14 ft aluminum model, with a max horse power of 25, will haul in a stringer with more fish, and bigger fish.
How to Find a Fish Finder
Not in a store, at the dock. Go out to the dock early in the morning and watch the guys back in their 25 year old boat, with a 35 year old motor, hitched to a 20 year old GMC half ton with a topper. There will be more than one pair of these crafty gents. They all know each other, and they all have their lake secrets. pay attention to each boat and pair as they leave, and remember which way they go. Now, launch your boat, turn on your gadgets, and go find your own fish.
After a couple of hours have passed, pull up anchor, or your trolling motor, and cruise the lake. Mark the locations of where the old guys in the Lunds are. Chances are they are all close to their own honey holes. Likely they have been catching fish in those locations for the past 20 plus years.
In the evening, watch at the boats as they return to the docks/boat launches. See which boat had the best day, then make that your first destination for tomorrow morning. When the old guys arrive tomorrow, give them the lane, they have the rights on these waters.