According to a thread on Apple's support forum, the new iPad users are annoyed by unstable 3G connections. The discussions on this matter are growing in popularity, as more users report similar problems.
New iPad owners complain about their devices have been losing the 3G connection. The problem doesn't seem to disappear until the iPad is reset. The majority of the users who are affected by the problem seem to be from outside the US.
"3G icon is visible and signal is strong but safari tells no connection (other programs don't have connection as well). Switching to airplane mode and back doesn't help and reset (off and on) always helps (...).I noted that it appears after long idle period," details V0vets.
Other users confirm that the problem appears after a long idle time and resetting the iPad seems to be the single solution. Jjaredwfs23 noticed that the unstable connection appears after switching from a Wi-Fi network.
Some users suggest that the problem might be caused by iOS 5.1 bugs. So far, Apple hasn't acknowledged the situation but they have promised to fix the issues related to poor Wi-Fi connectivity.