My company has an app that gets released every cpl weeks. One week we were rejected for auth reasons, except the screenshot of the login attempt in the rejection had mis-typed information. Delays aren't even always the developer's fault!
I've had an app that's been approved for over 6 months, with a new version every one or two weeks and it's always a coin toss. There are a number of times that I've released an update just to change an image in the app and the app gets rejected for not having enough content. Yet it's been approved over a dozen times without any change to the amount of content in the app.