I've now had an Apple iPad since the beginning of the summer. Heres a summary of my thoughts on this device:
1. Having a device which powers-on instantly is more convenient than a laptop. Its particularly useful when you want to grab it to use in bed, or when travelling (train, plane).
2. The user-interface is very smooth and slick, its a pleasure to use.
3. The availability of content is great. Via the app store and iTunes you can choose from a vast array of apps and books/films/music. Equally, once you've learned how to do it its pretty easy to convert your own films to put on the device.
4. Its really great for reading web-pages, particularly blogs.
1. Its too heavy (no-doubt this will be dealt with in future models).
2. The lack of a keyboard really limits its use. For example, when travelling, I still need to take a laptop with me too, I can't just take the iPad. And when you are trying to minimise the amount of weight you are carrying - and you already have a laptop and a smartphone with you - the iPad just just seem like an over-indulgence. Basically the ipad is better suited to consuming information than in creating it (ie watching films, web and photo browsing and reading, as opposed to typing).
3. Its hard to use privately on a plane or train: the people near to you can see the screen easily. For example, if you want to browse your email on a train, its harder to do so privately on an iPad, compared to a smartphone.
4. Its just another device to carry: as already mentioned, if you are carrying a laptop and a smartphone already, then you dont really NEED the iPad with you (although it can be more convenient for reading, and for powering-up for quick web-browsing).
5. As theres no USB port, and it doesn't easily synch with microsoft office or google docs, its functionality for work-type document creation and editing is limited.
The iPad is a beautifully constructed device, but is more a luxury item to carry around than a smartphone or laptop (which are essential for many of us). Its best uses are for consuming information rather than creating it. It really comes into its own as an ebook reader that can also do other things, and for reading web-pages its great. If you like to do a lot of casual web-browsing and a bit of reading around the house (in bed, on the sofa) and/or when you travel you can do without a physical keyboard, the iPad could be for you.