Updates undergo changes only if (major) issues are found during alpha and beta testing. A new release is made to replace the previous one, then it begins progressing through the channels anew. They're not any worse quality wise, most of the time they're the same ones that reach stable soon after. Given the nature of release channels, the security of your device can be technically superior to those on stable, as small as the time window is.
On the rare occasion something does show up usability may be temporarily affected but major stability issues are out of the question really, there's too many safeguards in place. You can't downgrade to the previous version without a full reflash so you'd need to wait for us to release the next update to fix whatever problem you came across. Don't let that deter you though, you're not bullet proof against bugs on stable either, seeing as we have way too few users reporting problems on the alpha and beta channel.
You don't need to do anything special either, simply use your device as normal and if anything is off give us a shout. It's greatly appreciated!