Apple tends to be more cautious about this than they used to be. You can be sure that Apple did extensive testing on all devices that might run the latest version and only the ones that would work well would get the public release version.But if older devices get upgraded and they don't work smoothly, they would get stuck there.
If you upgrade right away after a new public release of iOS and aren't satisfied, you can downgrade until Apple stops signing the previous iOS version.
Last edited: