Most common iPad complaint I've read thus far:
1. The touch screen is so reflective it "kicks up a vicious glare in a well-lit room and practically doubles as a mirror in full sunlight."
2. The iPad's light sensor "doesn't seem to work at all" the brightness didn't change when moving from "bright sunlight to a darkened room." (most likely a software fix)
3. Apple forums and its official support site are "jam packed with user complaints" about the iPad's weak WiFi signal, says Alan in Product Reviews. The "positioning of the antenna" seems to be the problem it's located behind the Apple logo, which is not the "ideal position for the best signal." As it is a hardware issue, this could be a "huge problem" possibly even triggering Apple's first-ever recall.
4. "It's pretty clear that typing is a secondary function for the iPad," reports Brian Lam in Gizmodo. When the iPad is in "landscape mode," the keyboard is difficult to touch type on without placing it on a "slight angle" not easy without a kickstand. In "portrait mode," the iPad is too heavy to keep typing up for long. Because its backside is curved, when placed flat on a table, the iPad rocks and rolls when one attempts to type. Of course, you can always buy a bluetooth keyboard for $69.
5. The USB charge cable draws more current than most PC USB ports can supply by the well-published standard spec. Using a USB connection to charge the iPad's battery is also time-consuming affair, says Brennon Slattery in PC World, requiring several hours. Also, too bad for you if you're a Windows user the iPad won't charge at all from the USB port of a PC. To me, not such a big deal since you can use the AC recharger that comes with the iPad instead.
6. Very slippery and relatively heavy (because of the large battery). Easy to loose hold of and will break hard if dropped only a few feet.
And some issues that were known before purchase:
7. Only one app can run at a time (because it uses the IPhone OS).
8. No standard USB ports (need a dongle from Apple), no SD slot, no HDMI out, no camera, low RAM that can't be expanded.
Finally, hardware wise, it's basically an iPhone with a large screen:
https://gizmodo.com/5510191/deconstructing-the-ipads-a4-chip-its-still-a-giant-iphone
Still, it has the typically slick Apple user interface they come up with for every device they make. If I actually needed one or if it cost $299 instead of $499, I'd buy iPad v2.0 when it's released.