I don't use DAB.
In the 1970's and early 80's, FM in the UK, both commercial and BBC, used to be world-class, but something went wrong as increased compression and radio-loudness-wars started up. DAB at 256 was deemed good enough, but the powers that be settled on 192, which is bad on some voices and leaves no wriggle-room for distorted source material apparently.
Good radio 3 live broadcasts aside, I really don't think 'sound quality' comes into it these days and my assertion about the compressed DAB feed being syphoned off to the FM feed came from an engineer.
DAB at it's best should sound amazing. But as usual, it's been compromised and has been outdated for some considerable time I understand. My experiences of internet radio are very positive, however and I have very positive vibes about a radio 2 show ACDC's Brian Johnson did a while ago, the iPlayer stream sounding truly excellent on both speech and the wonderful music he played.
Tear down these walls; Cut the ties that held me
Crying out at the top of my voice; Tell me now if you can hear me