[Capt. Debbie]

I love Foruno too, but they are probably some of the most expensive too. True side scan really needs multiple transducers to be good. Foruno does that but we are now a multi-thousand dollar system

Never had much luck with Hummingbirds in salt water.

Lowrance is a very good brand and has been doing it for years. That's what I have now. Good solid readings up to 22 knots. But that's more of a function of transducer location- aka keeping air bubbles away from it.

Garmin in very good too and we have them on the Tow boats for years in color w/ plotters and one w/ Radar too. Reliable.

FACTORS-
1- Bigger screens always cost more. What fits and what becomes redicuolously large are factors.
2- Expansion. Some system allow you to add stuff later to talk to each other - Like RayNav, Garmin. Usually they need a centralize stand alone interface box. This needs room for itself too.
3- Multipurpose. Some units are plotters and FF. Some even add radar into the fray. Like Garmin or RayNav.

I guess the bottom line is how much to spend and how deep into his set-up do you want to go.