My take on electronics is I want to catch just as many and just as large as any high level tournament angler. Actually more since I don't have time constraints or limits involved with tournament fishing. My time on the water is not less valuable than any touring pro or fishing guide. There is no higher level than my quest to catch fish.
I want the tools to show me where they are, why they are there and if they seem to be catchable. Doesn't make any bite though. That's my part.
I also want to know where they are not so I don't try to do any catching where there is no catching possible.
There are low end, mid range, and high end sonar models that do most all the sonar technologies available.
Get the most within your budget that has the technologies you will take the time to learn how to use. There are four major brands that have the side looking imaging, the down looking imaging, traditional 2D sonar, GPS with and without mapping. There are no bad choices, just some do a little better than the others for some functions.
Garmin, Lowrance, Raymarine, Humminbird