I guess I should supply a warning: serious technical wonkery ahead.
Paul, a member of the Stereo Club before it even existed, sent me this marvelous link on the topic of HD radio self noise, otherwise known as digital side band hiss. The author is Brian Beezley. This is a very dense exploration of the effect and its mitigation, complete with 8 by 10 glossy photos and a list at the end of vintage tuners that might avoid the issue to some degree. Highly recommended despite the trepanation required to relieve the pressure on my brain.
Paul also included this equally informative link on the remarkable Sony XDR-F1HD tuner. Let Paul talk for a moment:
I have this tuner and the specs documented on this site are true. Reception of analog signals is unbelievable. It isn't the best sounding tuner but its front end and IF selectivity performance is without parallel. Simply put, I receive, in stereo, stations I've never heard on the dial before. It's a cheap $100 plastic box and HD radio isn't the best sounding for FM but as a signal grabber, it's truly amazing.
And lastly, here is Brian Beezley's web page. Impressive.