Not sure about your last sentence, but I'll give it a go.
It's going to depend on the broadcaster, actually. Properly done, the difference is as night-and-day as an FM broadcast vs a CD playback (that's an actual CD, not a low-res mp3 rip of one). Given the multiplex nature of analog FM stereo, the separation is what really gets your attention.
Walking the fine line between jaw-dropping and a plain ol' yawn.