It seems to depend an awful lot on where you are in the world. I've rarely -- not never, but rarely -- had problems with Apple Maps, and I tend to prefer it to the Google Maps iOS application. But, I also live in the San Francisco Bay Area, which almost certainly makes a difference. To be fair, I've also had no problems with it in Portland, Seattle, Kansas City, Lawrence (Kansas), Eugene (Oregon), St. Louis, and around Tampa Bay. But it's not lost on me that all of those are not only in the United States, they're all pretty urban. (I've heard anecdotes of Apple screwing up in urban areas, too, but for me it hasn't behaved any worse than the other mapping apps -- Google has sent me to a few weird places.)

I think on the whole it's good for Apple to be taking control of their mapping back end, although I suspect it would have been better for them if they'd started by, say, buying Here (the former Nokia mapping unit).