Humminbird 678 cHD was my choice . . .

[Expidia]

Ordered the Humminbird 678CHD (sonar, no GPS) paid $334 with free shipping and no tax. Was going to go with the 718 for $199, but after I spoke to Humminbird support they said the 718 came out in 2009 and is discontinued, but still available.

Also the 718 is B&W and for the extra $135 for color . . . I know every time I would have looked at that hard to see B&W screen, I'd be kicking myself that I did not go for the color model.
It's shown on Humminbird's website as one of the US2 compatible models. I ordered the cable adapter too for $30 to work with the Ipilot's built in transducer (but the built in transducer shows in SD only).

 

[Expidia]

Ram aluminum vertical swing mount bracket came today. It's "the BOMB" and worth every penny. Paid $68 and another $11 for two day Fedex.

I needed a bracket to sit low enough to be under a tight fitting custom trailerable cover with the FF unattached. The 678 Humminbird is a color fish finder only, that can also be easily read in bright sunlight when fishing up in the bow seat. This bracket is light weight and allows the Humminbird to snap into it's quick release holder "with no wires to connect each time" other than the screw in connection of the built in transducer in the Minn Kota iPilot troller. Swings away and tucks away nicely into that corner in the pic below.

I still have a 797 at the helm which is a combo GPS.

I might buy a 2nd upper portion of the base where the Humminbird quick disconnect base attaches and then trim those sides off, file smooth and paint the cut ends . . . just for aesthetics. This way I'd have the full base too for future mounting of a bigger unit, before Ram stops production of this model's base.

But check out this sweet installation using Ram's 109VU verticle mount bracket below.