I was talking with a friend of mine last night on the iPhone. She was complaining that her iPhone was working poorly, and she was frustrated with it. I asked if she had updated to iOS 6 yet, since sometimes a restore cycle can clear things up. She told me, no, she wasn't, because she heard maps were terrible. I said, "did you hear they are terrible, or have you used them and think they're terrible?" She said she heard only. Interestingly, though, she said she had been using turn-by-turn with "a voice telling her when to turn." I asked her to go to Settings and check, and sure enough, she had updated and actually liked new Maps.
I don't deny that new Maps aren't at the level that GMaps were, but they're not really that terrible, either. Unless you required a feature that is gone now (transit, which I don't), then it's really not so bad, at least in my experience, and has improved since the betas.