Apple's AppStore reminds me of Google AdSense policy of isolation and almost inexistent customer service. If they ban you: They ban you. There's no possibility to discuss things.
I've had 2 great experiences with them, both involving multiple calls over a week's time solving Adwords account problems. (I'm only managing ~$15,000 ad spend per month, so it wasn't because I'm a big fish.) I do believe that's US support only, but I could be wrong. It's been the better part of a year since I've had to call in.
Anecdotally, my past experience with support for both AdWords and AdSense has been terrible. I'm glad they've got an 800 number now.
My office chair quite literally comes with better phone support than AdSense (or AdWords since I've never spent much).
They also apply their policies very inconsistently, and greatly favor large advertisers. I think their documentation is great, but they need to make a better effort to reach out to advertisers. I am not a huge fan of Microsoft's adcenter, but their customer service is incredible. Their number is always nice and prominent and when you call they will do anything to help, and work hard to get it solved then, where as Google will take their time.
Again this is a sample size of one, but google goes out of their way to not talk to you, they even hide their customer support chat service through several layers of help screens.