Power Flarm works and it works good.
A couple of years ago flying just SW of Parowan heading SW I got a ADS-B warning. It was the Beech 1900 airliner headed into Cedar City. I visually saw it over my right shoulder and keep on my heading. After a couple of minutes it was clear that we would pass very close. I changed my heading and got out of the way.
Last summer flying out of Crawford Colorado I got another ADS-B warning, it was a business jet flying right at me going into land at Montrose Colorado.. This was very close also.
Flarm is remarkable and is not that expensive or hard to install; if you don't have one get one, with the extra antenna and IGC logger connected to a large screen like a Oudie, it is awesome. And it is available NOW.