Rlogan / Jerry,
I'm working on a comprehensive ADS-B comparison at this time. Recommending on is really hard a they all have such different niches they fill, like ultra-portability, battery powered, AHRS, ADS-B In/Out, connectivity and more.
What level of traffic you are looking for really matters as the ADS-B out or "Transceivers" are the only way to go to the most traffic. They wake up the ground transmission so you see more than just the ads-b 978 out aircraft. I'll have a chart up on our site shortly with all the compatible units, prices and feature details. Thanks for your patience. Have a great evening.