In addition to the new iPad getting a bit warm when playing graphics-intensive games, it would appear that an unknown portion of early adopters are also having issues with Wi-Fi reception. A growing thread on Apple's support forum is filled with reports describing a range of difficulties with the iPad's wireless networking capabilities.
According to a bunch of disgruntled users, the new iPad has trouble maintaining a reliable wireless connection in places with strong signal. It also exhibits flaky connection that constantly drops or has no reception at all. Apple has not yet responded to these complaints at the time of this writing...