The key advantage this unit will have is the smooth scrolling interface that the iphone already has and I would expect this to also have. That and the app store which my wife loves - yes she has an iphone and I have to admit the finger scrolling interface is the best I have seen. Far better than my HTC touch pro 2.
However why do I think this will fail.........................
1> typing on a touch screen is silly no tactile feel plus you lose half the screen real-estate. Yes you can take notes in class or in business meetings - I can do this right now with my mini 9 (same size as the iPad - but thicker)
2> No multi tasking - I use the mini 9 for business, I'm using it right now - have open outlook, word, excel, web browser. What am I supposed to do get an email, open the attachment remember to save the file, reopen the email client reattach then send. close email open word work on a document - remember to save & close this reopen email client check emails - close down again reopen word doc. Just not practical for work.
3> Skype - ops can't have that either no webcam,
4> USB support - so I need a file on a USB key - ops left the dock at home so now I'm stuffed.
5> no ethernet - OK so no high speed connection other than wireless - pity we don't have wireless in all business locations.
My mini 9 has - multi app support, 3 USB slots, ethernet, Wireless a,b,g (upgradeable to n if I wanted), 3G builtin, GPS (built into the 3G card), VGA out & SD multi slot, Bluetooth, webcam. And a similar sized footprint (OK thicker than the iPad by quite a bit but smaller than a piece of A4 paper in both length and width) - only negative is the lower res display being 1024x600. All for a similar price point - yes, however no touch display the only thing it is missing.
Sorry but for me the iPad does not cut the mustard, too many compromises. Will it sell well and prove me wrong - only time will tell.