Don't Install iOS 9.2.1 Beta If You Don't Like Bugs
Avoid the iOS 9.2.1 beta, and really any early software, if you can't handle dealing with problems and bugs.
iOS 9.2.1 is early software, meaning, it's not done. Unfinished software is typically buggy and iOS 9.2.1 beta is no different.
iOS 9.2.1 beta users are already reporting numerous problems with the update and they include issues with Safari, Notes, Messages, and several system-wide problems that have the potential to be extremely annoying. These were found in the first few hours and we could see more emerge before everything is said and done.
On top of these, you have the potential for common iOS issues like battery drain, Wi-Fi problems, and more. For many of you, trying out an update that doesn't come with any major feature changes probably isn't worth the risk. Especially, if you only own one device.
Unless you're a developer, you do not want to install beta software on your daily driver.