Pre 4.3 this was the fact. Camera ceased to work and other functions aswell. The DRM keys did matter there. The tech guy from Sony also confirmed this.
Kitkat version though this is all fixed. And like he said to quote him "Nothing will change software wise with just unlocking a bootloader under Kitkat, aslong as you dont flash custom roms ofc."
So to translate this: The DRM keys aint used in KitKat. And it is very easy to confirm this yourself. Google the functions that people say will stop to work with no DRM keys. None of thoose has stopped to work with unlocked bootloader for me on KitKat 4.4.2.
And for the camera, the camera working worse under KitKat as you also can google and find information about. Unlocked as Locked doesent matter, and this is possibly one of the reasons why ppl still think, Bionz, X-Reality and other functions stop to work with unlocked bootloader.
But is it worth it? Well that is up for anyone to decide for themselves. Since KitKat, the phone aint working so well anyway imo. So if it would die on me i wouldnt care. I will probably not buy Sony in future though, they used to be good but something has happened.
Xperia Z1 - Stock kernel - .761 - Locked Bootloader
Xperia V - New display and working like a charm.