I've been thinking lately, and I actually just posted this status on Twitter:
It's true though, Apple doesn't bull**** or play around, they don't generally announce things way ahead of time(iOS 6, but iOS 5 is out and is not buggy). Like the new Retina Display Macbook, they pretty much just had it ready to go. Microsoft experienced this success with the Xbox 360 S, where they set it on sale essentially the day of announcing it. It was a complete mystery and it hit hard, like Apple always does.
I think they should've waited. I definitely want a Surface Pro for college. It will replace my laptop and then I'll get a high end desktop for Photoshop/Gaming/Video Editing.