iOS 4.2 was supposed to be delayed on the 12th of november but due to last-minute WiFi connection issues experienced by many users running the GM build on the iPad, Apple had to delay the final release to fix the WiFi bug.
The problem is basically, even if the iPad manages to successfully connect to a local network, the connection is lost after a few minutes. This seems to be the most common problem experienced by users. Other users are simply unable to use safari at all.
Apple released a new GM build of the firmware for developers which supposedly fixes the WiFi bugs. Lets just hope that it doesn’t have any other bugs to further delay the release.
As for iPhone and iPod touch users there seems to be no bugs or problems on running iOS 4.2 and to be honest im not really anxious to update my device to 4.2 as it hardly adds any useful features to your device, none really worth mentioning.