I hesitated before posting this, because I know a lot of people disagree, and some violently, and I really don't feel like rehashing it all over again. But you did ask for personal expereinces, so here's mine

I ride with earplugs and with music on. I still hear traffic, but I don't hear it from a long distance. I compensate by using my eyes. I turn around and look a LOT. I feel that hearing is very subordinate to eyesight when it comes to taking in my surroundings. When I take the earplugs out I hear more, and louder, but it doesn't feel like it tells me anything I didn't already know. If I have to ride home wearing glasses rather than my contacts it freaks me out, though.

Caveat: I ride either on city roads where there's traffic all the time, at not very high speeds, (i.e., I have to ride in a straight line at all times anyway, and there are very few vehicles "suddenly" turning up) or on bike paths where there's no traffic at all. I might choose to not wear earplugs if I rode on roads with little but high-speed traffic.

I think that if you need to wear earplugs, you will adapt just fine, but you might have to retrain the way you ride.