Sony now supports AOSP builds on our Z3 Compact...OK, what does that mean?

[oldDummy]

Sony Now Supports AOSP Android Builds On All 2014 Qualcomm-Based Phones

Could somebody explain to me what I give up if I do the research and install a pure version of Android.
What gains would Lollipop give my Sony Xperia Z3 Compact?
Speed? , features?
Does anyone know?
Sony's additions/bloat is minimal from what I see.
Don't think it would be a dramatic change.
I know loss of warranty is a byproduct.
What is the benefit?

 

[oldDummy]

I see where if no updates are going to happen then you are free to upgrade to the latest and greatest Android version.
So, in effect, it gives longevity to a phone after formal updates are non-existent.
Well, that's something anyway.
Kind of a big thing.....

 

[Restrictive]

Lose Sonys Camera tweaks, battery tweaks, display tweaks

 

[oldDummy]

Unlocking The Bootloader On Sony's Xperia Z3 And Z3 Compact Causes Poor Low-Light Camera Performance Thanks To DRM [Update: Sony Updates Policy Text]

Update: Sony has updated the text of the bootloader unlock warning on its website to be clear about the camera impact. It reads, "...the removal of DRM security keys may affect advanced camera functionality. For example, noise reduction algorithms might be removed, and performance when taking photos in low-light conditions might be affected."

This from early October....