I'm really not sure I'd call it a PC
I'm really disappointed with data input on my iPad. I was hoping the big keyboard would be nice, but actually in some ways it's too big to be easily 2-thumbed (text style) and too small to touch type - hard without haptic feedback anyway.
Before I bought it I'd have expected to use it to send emails, now I think anything over 2 paragraphs starts to get very painful. The same with commenting on El Reg. Maybe I'm being unfair because I touch-type, so resorting to two-fingers seems terribly slow. I'd say that handwriting recognition on my old tablet PC was just slightly better, as I could get to 3-4 paragraphs before frustration set in.
This stopped me buying Apple's Numbers and Pages apps, that I was expecting I'd get straight away. They also had some very mixed reviews on the App Store - I wonder if they've been allowed to stay up...
That, and the Apple lock-in / use-restrictions / difficulty of controlling data/files, makes me reluctant to call it a general purpose computer. Or if it is, only in the way that smartphones and PDAs are, so you could include Nokia as one of the world's biggest PC manufacturers too.
Not that I don't love it. My iPad gets at least an hour's use a day, often a lot more, with looking things up, reading The Register (sometimes while enthroned - for shame!), BBC iPlayer and reading email.
I'd personally define it as a big PDA, rather than a small computer. Unless maybe you use something like this: http://clamcase.com/