Stephen,
I'm sorry for any misunderstanding at the show. ADS-B receivers in general are great for weather and less inclusive of Traffic than a Transceiver. Have a dual band vs. a single band receiver will get you similar traffic while at altitude and linked to the ground TIS-B broadcast, provided a ADS-B out or Transceiver craft has woken up the tower broadcast.
The major benefit of a Transceiver is that it will send out the signal to wake up the Ground TIS-B broadcast for traffic. The ground broadcast actually has both the 978 and 1090ES in it as ATC is merging the data and pumping it out on the TIS-B ground signal.
The Dual Band receivers will help with the Air-to-Air traffic as it would receiver air-to-air signals from both the 978 and the 1090ES, but keep in mind most of the 1090ES is going to be over FL18. I hope this helps a little bit.