I've had two updates for my Sony headphones.
First update allowed the voice commands to support multiple languages, the second one was based on user feedback and allows you to turn off the voice prompts, and also to turn off the very sensitive touch-sensors on phones (I've done this as I don't use them and was sick of catching them and skipping a track I was enjoying).
Ultimately though, I do feel that companies should be transparent with what a firmware update changes, and allow the customer to make an informed decision whether to install it or not.
It's the same as BIOS updates on your PC. If the PC is working fine and there aren't any security issues, don't bother installing an update if all it does is add support for a CPU you don't even have...
Biting the hand that feeds IT
