Vincent Danen once pronounced the iPad a "giant iPod" and passed on the original device; however, caving to pressure on the iPad 2, he revises his opinion on its usefulness.
Recently Apple released the iPad2 and under pressure from some other household members, I obtained one. Having had it for a few weeks now, I can honestly say this device really does have some appeal. I can't compare it to the original iPad, which I've only ever used briefly and never owned, but I do have some observations on the iPad2 itself, from someone who has never used it. Perhaps these are indicative of the iPad in general; those of you who have used the original iPad will have to let me know.
The iPad2 is smaller and lighter than the original, but it's still quite large. When held, it's like holding a hard-cover book, just lighter. A lot of the applications that I use I already used on the iPhone, but the majority of them just look and act better on the iPad. My most often used applications are Daylite Touch and OmniFocus; Daylite Touch works on both devices and doesn't cost extra, but you will have to shell out for OmniFocus for the iPad. This bothered me a bit at first, until I had a chance to play with OmniFocus for iPad. I don't know if I appreciate the double-dipping, but OmniFocus on the iPad _is_ a whole lot nicer than the equivalent on the iPhone.
The larger screen offers a lot of interesting opportunities. Daylite Touch is so much more usable on the iPad, giving more information at a glance than the same application on the iPhone. This results in less swiping around and poking to get at your information. OmniFocus works great on the iPhone and is an indispensable GTD application, but on the iPad it's stunning, much more usable than the iPhone version.
There are also other applications for the iPad you simply cannot get on the iPhone, or wouldn't want to. Apple has the components of their productivity suite iWork available for iPad: Numbers, Keynote, and Pages. These are not available for the iPhone, and I can't imagine working on a document or spreadsheet on such a small screen. To view or reference, sure, but not to edit. Other offers, such as DataViz's Documents To Go works on both the iPhone and iPad.
Having spent some time with the iPad 2 now, I can certainly appreciate it. The instant-on availability of having something small and unobtrusive kicking around the living room, that provides a really good web browsing experience (as opposed to on the phone) is definitely nice. Apps like GarageBand are pretty slick; my daughter is having a lot of fun with it and I have to admit it is quite incredible.
Will it replace my Macbook Air? Not a chance! I need that keyboard and there are too many programs I need that the iPad2 simply won't provide, or just aren't convenient on a tablet (for instance, while iSSH works good as an SSH client, there just isn't enough screen for it to really be useful, compared to a laptop or desktop). But other things, like checking TODO lists and web pages, are seconds away with the iPad2. It's not as convenient to put in your pocket like an iPhone, but it's portable enough that it isn't unreasonable to carry around. The other thing I found was that typing on the iPad2 was so much better than on the iPhone, and I can type with decent speeds and pretty good accuracy. I couldn't imagine writing this article on it, but it certainly allows you to compose emails that aren't as terse as they might be on a phone.
For me, the iPad2 is a great quick reference tool. It's easy enough to carry around, provides a good viewing size for the browser, and offers a number of compelling apps to work on documents, spreadsheets, or presentations. It is by no means a netbook-killer, but it definitely fills a role in the form and function department, just because it is so portable. If you're in the need for a reference tool: web browsing, checking email, referencing documents, managing tasks and contacts, the iPad2 is really handy.