Best portable Fish Finder (humminbird fishin buddy?)

[flygoddess]

I admit, color screen is cool, but what does the different 256 colors show you and how does it really play in fishing?
I have the black/gray/white screen. It is gray for soft bottom, black for hard bottom and FISH.
Not up on this, but I don't see where red/purple/orange/yellow....etc really out performs.
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