I have tested on two devices now the Non Branded BTU UK 5.0 and after a Factory wipe things are impressive as Google automatically does a optimization to make surre apps still on the phone are compatible and others removed, it seems that third party apps were causing issues running in the background after it updated
On the Other device Running Vodafone rom OMG major battery drain as there are alot going on the rom was alot bigger
there Apps made by third party companies are not working and there own update app was trying to update constantly, Now the stock BTU got another update to fix the Mute fix, but no fix for Vodafone.
I tried a factory wipe on the Vodafone but there was no fix so i had no option but to roll it back but that was easy as Kies helped as it offered me two roms the Original and 5.0
There are other issues on the site but speeking out about them can get you Banned the main is RCS and this allso has issues as that also is the pre 5.0 version and is having issues
It looks like who ever has put this rom together has not checked the apps, The controversy around RCS still goes on HTC users felt the most grief but even on 4.4.2 its a night mare if you unlock the phone and it goes to another network the company using RCS still get a copy of your messsage sent via data.
This is why samsung told me how to debrand a branded phone to stop this
so for the stock BTU rom with all the white is very good after the last update the battery is back to normal state again
so Stock BTU gets four stars, but a Network version is a No no stay with 4.4.2 and check the network forums out for issues
eg
Samsung Galaxy S5 - Vodafone eForum