But that was my point. Most aircraft have 1090 and ship to ship will be more prevalent on this frequency. Of course UAT can operate ship to ship, and both operate through ground stations. Most installations with 1090 in/out are also UAT In literate. A big reason I went with the GTX-345 was 1090 In/Out and UAT In. For me I place a value on getting traffic information directly "ship to ship" as I fly in areas were coverage is thin. Activating synthetic vision in Foreflight from a certified panel device was also a priority for me.
I'm very happy the FAA went with 978mhz UAT as supplement to the international standard of 1090mhz. I have no fault with people who decided on the minimum of 978mhz out only. The answer for my plane was a fully featured GTX-345.
You still don't get it.....if you have a dual band ADS-B receiver, you do not depend on towers for traffic, so the "coverage is thin" does not matter.
If you have a dual band ADS-B receiver...like a Stratux, Stratus, GTX345 or whatever, you receive all ADS-B traffic "ship to ship". The only additional traffic you will get from ADS-B towers is TIS-B traffic, plus weather. The towers DO retransmit ads-b traffic info, but you should receive that without any help from the tower transmission.
The ahrs in ForeFlight works fine with my Stratux....remember ForeFlight is not certified and nether is the ahrs in ForeFlight, although it is a great tool that I use all the time.
With that being said, I have installed GTX345 units in aircraft with GTN430W so the traffic displays on the screen....that works very well, as it should. If I had a Garmin GPS with that capability, I would probably have gone route.
Sitting on the ramp outside my hangar, I receive traffic from over 100nm away which increases when I am at altitude....not too shabby for a Stratux. I usually receive 3 or more towers in flight for weather and TIS-B traffic.
So it dpends on your intentions...if you do not fly above 18000ft and stay inside the US, UAT is fine...so is 1090ES. The OP already has UAT capability...it is his decision.