Size and Weight
The iPad is a beautiful device. It weighs 1.5 pounds but still feels heavy in the hands. While it is light for a computer, it feels heavy compared to a paper notebook. It is about 1/2 inch smaller than an 8.5 x 11 sheet of paper on the sides and about 1 inch smaller vertically. It's larger than a journal but smaller than a college-ruled notebook. At half an inch thick, the iPad feels small and easy to carry. I prefer to carry it in the Apple case which is a $39 add-on option.
The screen is dazzling and easily readable with its brightness at the default setting. I set mine even lower and get even better battery life. In bright light, the brightness needs to be turned up a bit and the iPad is not really readable in direct sunlight. Reading in the dark at night is easy when in reverse video. The screen is glossy and seems like a magnet for reflections in whatever room I am using my iPad. It's easy enough to adjust my posture to avoid most reflections but I'd love to find a matte screen protector. There is no screen cleaning cloth included with the iPad but the screen is a fingerprint magnet. Fingerprints are more noticeable in brighter lit environments like outdoors.
The viewing angle of the screen is wonderful. I can set it down on a table in front of me and still read it easily, though perhaps not quite as easily as having it tilted up but not nearly as bad as all the laptop screens I'm accustomed to.
I have had no reason to doubt the accuracy of the touchscreen and I do not have any dead pixels. It's pretty easy to check for dead pixels. Simply toggle between two vastly different color schemes in the included wallpaper or triple-click the home button to get reverse video. If a pixel was stuck black, you'd see it pretty quickly.
This is a touchscreen device so switches are kept to a minimum. There is the home button, which can wake up the device. There is the power switch, which can wake or sleep the device. There is a rotation lock switch and two switches for up and down volume control.
There is a standard iPod dock connector at the bottom and a headphone jack at the top. Apple has promised a VGA output accessory, and a "camera connection" accessory which should be able to read SD cards. A usb cable and wall wart are included in the box with the iPad.
The wifi iPad model supports bluetooth and wifi. There is an ubran legend that we got GPS but I don't believe it. Pairing Apple's bluetooth keyboard is easy. I have not tried to pair a mouse but I plan to try it later (A mouse is part of the kit I'd hope to use with my iPad for remote control of my Mac). When a bluetooth keyboard is connected, the onscreen keyboard stays hidden and I have a very "computer like" experience using my iPad.
The iPad wifi works very well in every location I have tried it. I have an Airport Extreme at home and it has worked flawlessly. Every hot spot I have tried has worked flawlessly.
Unfortunately the iPad does not seem to have implemented some network protocols I'd like to see. I bring this up here because these are OS issues rather than app issues. There is no AFP and no SMB. There is no built in screen sharing application and I have to resort to third party software to control my Macbook. I'd really like to see my iPad show up in Bonjour with a dropbox folder so people can send me files if I want them to. I'd like to be able to browse network drives from the OS, not third party apps.
If you fire up the maps app on the wifi iPad, you'd swear you had gps. If you take a drive with the maps app, your location gets updated in fits and starts as you pass wifi hotspots. Eventually, as you get out into the corn fields, you get an "unable to determine location" popup once the software gives up finding any location via wifi. This caused some confusion in the forums over at Macrumors and users argued back and forth about whether the iPad had gps. It does not.
The folks over at iFixit have taken apart an iPad and given a detailed overview of how it is put together and what's inside.
Updated 4/19/2010: The second video above is from TechRestore.