It's inferior in two ways:
It runs a mobile phone OS. You can do a lot more on a PC OS, and there are far more programs available for Windows/OSX/Linux/etc than the measly 150,000 apps on the iphone os, most of which aren't any good.
It's also inferior to the iphone/ipod touch, because it's too big to be carried around in your pocket everywhere you go.
Mobile OS, with a kernal that's used in the Desktop Area. And when you say Desktop OS, that's exactly why the Tablet Program failed in our school a few years ago when we had a trial, and 3 years ago - when we wanted to give it another go - it failed too. The reason wasn't that Tablet Technology wasn't good enough, but that we really couldn't use a Desktop OS that wasn't designed for Touch - it just... Didn't work. We even tried Linux, but that too didn't have the support and programs we required.
It's not all about not having a Desktop OS that is designed for Touch, but also about not having enough Programs that are designed for Touch. Although the PC has Billions of software, unfortunately, nearly all of them aren't designed for touch, and that was a big issue for us. As a school, we tried to contract someone to create us a onscreen keyboard that was well... Usable - it didn't work.
In respond to the multi-task issue, we are actually quite happy (and so are the students we interviewed) and using only one application at a time. The students understand that this device will mainly be for studies, whilst their own iPhone, iPod, MP3 or what have you are their personal media device.
They were happy about running one application at a time (though I do agree about your issue regarding copying between PDF, Email and Word Processor - I'll addres this later) because it would help their own workflow, and I quote 'It's not a bad thing, not really. I mean, if we were allowed to multi-task, I'm sure we'd continue doing what we do now... Which is basically using our desktop to game. When the teacher comes, just flash the screen away, and back when they leave... I personally think being only able to run one thing at a time would help myself work better and more efficiently'. That's a plus for the students, and the teachers.
About the Word Processor issues, we are trying to see if we can find anyone to develop a word processor that is has PDF reading support, email support and even allow storage on the device and wireless sync to their computers / printer servers.
Now, to some legitimate issues. Textbook, we're not sure what's going to be there, what's not - that's an issue for us.
The Video Out is not very high quality, which isn't very good for those of us who would store videos and show the class, and well - Presentations too. However, our interactive whiteboard is around the iPad Resolution, so it is fine - but that isn't future proof enough for us.
The keyboard price is high - and we're not sure how many we need, as some are more Pro-Touch Screen and some are Pro-Hardware Keyboard (though most are saying they're prefer the Touch keyboard) - so that is also an issue.
Without trying to derail the thread, I personally think the lack of Flash is an issue - just because many education 'games' and 'information' uses Flash, but we believe that these will be covered in E-Books which are hopefully interactive. We too wish that Flash would 'disappear' as our students themselves agree that it's a major hog.
One online non-flash software our Art Department uses is MugTug's Sketchpad which you can find at
http://mugtug.com/sketchpad/. It's a very good site and software, and it's free! Try it!