I have the Garmin GTX345 (I actually have the R model, the remotely mounted transponder, controlled via a GTN750).
Beautiful easy-to-use transponder along the same lines as all of the other GTX units. Does both 1090 and 978 In and Out. Receives ADSB traffic and weather in and displays it on both the panel-mounted instruments, as well as by bluetooth on my iPad (running Garmin Pilot).
The high end of the current GA offerings, but a great product.