I started with Garmin and Humminbird. The boat I bought had a couple Helix units and before I bought the boat I bought a Garmin Echomap.
Before I bought the boat I had decided on Garmin. I’m a budget guy and with Garmin you get more bang for your buck. The preloaded maps had my lakes, Humminbird didn’t. Garmin has QuickDraw where you can create up to 1 million (I believe) acres which is more than I’ll ever need, Humminbird you have eight hours, then you need to buy a zero lines card which is over $100. So Garmin was the right fit for me.
You really can’t go wrong with any unit. Humminbird has MEGA imaging which from the sounds of it, it’s better than Garmin’s UHD. Lowrance have fish reveal which looks like it would be nice to have. Lowrance’s live imaging is borrowed technology from Garmin, so it’s basically Garmin’s first gen live imaging so I doubt it’ll ever compete with Garmin. Humminbird has MEGA 360 and soon to be MEGA Live which has caused some to become head over heels in love with it even though to my knowledge nothing has come out to show what it is or what it looks like. Then Garmin has Panoptix, Livescope, their excellent mapping, UHD, and some argue the best 2d sonar.
Just keep researching, the more informed you are the better you’ll feel about your decision.