1. PDFs are much easier to read on a vertical-format screen unless said screen is very large (would need to twist modern wide-screen laptops sideways). Also, I prefer that my reading device is not heavy and that it is small enough to read while on standing on public transportation -- this way I can get heads up on things before arriving to work.
2. The ability to annotate documents directly using finger input is amazing (I am not talking about handwriting -- I am talking about yellow-highlighting passages and keywords without using the classic trackpad and cursor combo which requires a stable platform for it to be usable).
3. The ability to just take the PDF/document/notes/whatever and bring it over to my boss next door is irreplaceable. Laptop is too heavy and cumbersome to hold with one hand, and email/file-sharing is cumbersome as well -- bosses are generally unwilling to listen to their subordinates tell them to open this or that file while they are in the middle of something on their screen. This is why most offices have stuck with paper for so long -- it is great to be able to carry something in your hand and just show it to somebody across the floor. Likewise, it is easier for my boss (who also has an iPad) to just show me some document without having to print it or email it to me or walk me over across the lab to his computer.
"Laptop is too heavy and cumbersome to hold with one hand, and email/file-sharing is cumbersome as well -- bosses are generally unwilling to listen to their subordinates tell them to open this or that file while they are in the middle of something on their screen."
The importance of this is under-recognized.
A friend realized it is much cheaper to just pre-load an iPad with demo software and mail it free to a prospective client, than to fly to said customer and arrange for meeting times and persuade them to load & run software on their computers. Open an envelope, turn it on, start using the product - send us a check and we'll keep it on and send you more. "$500, it just works" is _cheap_ for what it buys.
