As someone that has an iPad I will say that they are great for those that consume data. Reading books, agendas, reports,etc. Slim, fast, relatively virus proof (iOS5 is separate from any other operating system and as of right now there are no known virus with the iPad...although I'm sure that'll change eventually). They're instant on/instant off and can go for days without needing to be charged.
They're not so great for those that CREATE content however. many iPad apps are skinnier than their pc/mac counterparts, and while they have basic functionality, they don't have all the bells and whistles. For example a word processing program that lets you bold, italicize, put in a few bullet points but nothing 'fancy'. TO be fair however, most of what they allow you to do is what most people do.
You also have limited capacity, no more than 64 gig, while for that same price point, 799, you can get a good laptop with hundreds of gigs.
I have issues with backing up over the cloud. I've personally dealt with the cloud 'eating' all my contacts. Poof, they were all gone and I had to rebuild. So while it exists, it's buggy. I have chosen not to use it, not just because of my experience, but also I have issues with allowing some third party to have my data and protect it...I don't trust them, not to mention any data gathering location is a hacker magnet. My own paranoia 🙂 HOwever in the scope of the government and all the data that can be on their units, there could be some very sensitive stuff out there.
There's also a lack of upgradability...you can' t add memory to an iPad. And you are totally tied to one retailer - apple - and their app store...and what they choose/don't choose to allow in there.
Apple has a bad habit of limiting functionality on a whim. FOr example, a year or so ago you could use the camera connection kit and plug almost any USB device - via the camera connection kit - in and use it to gain extra storage...then they decided to limit that for reasons only they know. There was another massive kerflulffle a few months ago when the iOS5 operating system had major battery issues...so have too many people on the same device and you open things up to one programming error effecting tons of people.
THere are also apps on the iPad that you are not allowed to uninstall. Facetime, newsstand, gamecenter etc...I don't want then, dont' use them, but I can't take them off. You are also not able to password protect your e-mail. You can have a lock code on the device in general. You can use webmail only and use a password for that, but the e-mail app itself is not lockable. There is also only so much content control you have. Many schools and parents have bemoaned their inability to control what the kids have access to or can change.
Don't get me wrong, I love my iPad. It's a great tool and there are things out there that help with its functionality, like the zaggfolio that basically makes your iPad into a small laptop with the addition of an external keyboard. But there are also limitations. I've found some great apps that work quite well (documents to go interfaces with your computer and you can even wirelessly sync documents without going through iTunes). But there's also things out there that don't work. ANy flash based websites will be off limits. Flash is not nor will it ever be on the iPad. (and Adobe has ceased production on mobile versions). Java also has a 'sometimes it works' level of functionality on sites. And there are other issues with mobile safari not totally working with some sites.
It's good, it has its uses and it holds the promise of a future where something like the iPad will have fantastic functionality and probably be as good as a home PC.
So I think for data consumption, reading of reports etc, they're fine. But they're not going to replace a laptop anytime soon. they lack 'oomph', they lack security and they lack content control.