Been listening to HD channels around L.A. I predict it is a doomed technology. It can't compete with satellite.
XM is rock solid. HD drops out if you look at it wrong. On the HD2-HD3 it mutes because there is nothing to fall back on like the main carrier.
Also, the selling points of HD were better audio, more user services, and multi-channel. But, it only sounds better when it works, the "services" require stations to pay license fees to use them, and HD2/3..are worthless. There's no revenue in HD radio, so stations are turning it off.
The good news is, all the HD gear displaced other gear that will make its way into the market.