So, I had a chance to try out an Apple iPad the other day.
Let me preface this by saying (and this is just my own personal opinion; please don't hate me) I'm not a huge fan of Apple. I do own, and love, an iPod Nano that is several years old. However, ever since I used Macs in high school and had to use a PAPER CLIP to get the darn things to eject a disk, I've never quite recovered.
So it was with a bit of a jaded eye that I turned my attention to this new toy. And after my experimentations, I still consider it to be a toy. For one thing, I just can't quite get into the touchscreen mentality. I've touch-typed ever since I learned how in the most useful class I ever took, and I can get a fairly decent WPM going when I put my mind to it. That's how I managed to write two novels each in about a month. But touchscreens make touch-typing just about impossible - you need feedback, and those little bumps that let you know your fingers are on the home row.
Another thing is the fact that the iPad doesn't come with a stylus. You can buy a third-party iPad Stylus, and if you have an iPad, I highly recommend that you do so. The thing is, I stopped finger-painting a long time ago, and there's a reason for that: I learned how to use tools, like a pen and a pencil. Going back to writing or drawing with your finger is not an easy (or pretty) thing.
In conclusion, I could see an iPad being useful if you wanted to take down notes on the go or brainstorm away from your desk. And if you had a lump of cash sitting around with nothing else you wanted to spend it on. But I still see it as more of a procrastination device than a serious tool for writers. Just my 2 cents.