Don't Install iOS 10.3 If You're Worried About Problems
If you're having an excellent experience on iOS 10.2.1 or below, and iOS 10.3 fails to excite you, consider holding out.
iOS 10.3 users are already complaining about Wi-Fi issues, various issues with Bluetooth, activation issues, problems with various third-party applications, installation problems, UI lag, random reboots, and battery drain issues. Some users are also still seeing the infamous "30% battery" issue.
If you're feeling comfortable with your current version of iOS you might think about waiting for more iOS 10.3 feedback to arrive. You might also think about waiting for the first iOS 10.3 bug fix update.
Remember, there is no way to downgrade to iOS 10.2 or iOS 9 so you'll want to be sure about your move to iOS 10.3.