Expect iOS 10.3.3 Problems
The iOS 10.3.3 update is going through a beta but that doesn't mean it will be perfect. You can expect problems to slip through the cracks into the final version.
Beta testers have already discovered problems lurking on the software but many of these issues will get ironed out before the update is released later this year.
That said, you can expect the iOS 10.3.3 update to be plagued by the same general problems that plague every iOS release: Battery drain, broken Wi-Fi, busted Bluetooth, issues with Exchange, problems first and third-party apps, random reboots, and UI lag.
This is precisely why we recommend preparing for every update, even small maintenance updates like iOS 10.3.3.
It would also be a good idea to get familiar with fixes for iOS 10 problems so that you're prepared to tackle any issues you see on your device.