AirPods Pro certainly has much better bass with ANC on, and I'd say overall sound quality too. It also sounds louder, although I'm not sure if that's just perceptual: higher sound levels are fine to me with ANC off, but are unbearably loud with it on. That's in both loud and quiet surroundings.

I've noticed this as well. When I have ANC on in like a grocery store with music playing at a comfortable volume, then turn it off, I can barely hear the music.