On my tablet, the update was not so well taken. Some applications (mostly games) don't have sounds, some have lost certain functions (accessing memory, mostly) and my time announcer started announcing the time at random times!
The Doze function seems to be a reasonable thing to have, but it's more annoying than the daydream feature, which didn't work anyway.
It looks like if you, as a developer, have an application with any system functions, you need to make sure you have the right permissions.