I've had ADS-B Out for about 2 3/4 years, utilizing a KT78 transponder tied to a 430W. I get ADS-B In on a Stratus 2 and an iPad Mini 4. That gives me 1098 out and both 1098 and 978 in.
I Bluetooth the aural announcements that ForeFlight provides from the Mini 4 to my DC One-X headset, which include traffic alerts as well as runway and altitude alerts, so I don't have to concentrate on the iPad screen. But those same alerts also pop up as windows on the screen.
What I noticed most when I first had the ADS-B Out installed was the increase in traffic coverage. That's because the system was triggered by someone else's "hockey puck" when all I had was the Stratus 2, but now I was generating my own "hockey puck", which caused more traffic coverage to be transmitted.
However the details of the system work, my experience has been that the system works well. It's much better than the radar-only system. For instance:
- When I fly to or over the San Luis Valley, without ADS-B Out, Denver Center would lose me right after I passed any of the ridges if I was at 13,000' or lower. With ADS-B Out, Denver Center "sees" me down to about pattern altitude at Alamosa. That's a fantastic difference of about 4500'. At my normal altitudes, I have complete coverage all the way from Greeley to Durango.
- When I fly across Nebraska at lower than 10,000', Denver Center always "sees" me with ADS-B Out. Without ADS-B Out, there were large gaps in coverage from about mid-Nebraska almost to the Nebraska/Colorado border.
It makes flight following realistic, for ATC to be able to see my airplane at lower altitudes. It also reduces IFR workload a little, so that I don't have to calculate next reporting point times.
So the combination of better traffic coverage and the ability of ATC to "see" my airplane at a lower altitude are the benefits I've seen with ADS-B Out.
Incidentally, whether ADS-B In is receivable on the ground or at lower altitudes depends on the location of the towers. If there's a tower on the airport property, there will be coverage to the ground. In my case, the nearest tower to Greeley is close enough that I generally start receiving weather shortly after take off, so just below pattern altitude; it's not close enough to receive it on the ground.
All in all, I'm glad that I didn't wait. No, I didn't qualify for any rebates, but I did have the benefits of ADS-B Out long before the first rebate was announced.
Cary