Yeah - don't.
The Z3v and Turbo both have great battery, BUT the Z3v has a better display (despite the higher density of the Turbo) and speaker sound that rivals the M8.  The *only* thing I don't like about the Z3v are those bloody doors.  My USB port cover won't stay close and Sony doesn't want to hear about it.  Unless I want to pay bigtime for repairs.  But still since I went Qi with it and coaxed the door shut, I'm waaaaaay happier with it than the Turbo.  I went through three Turbos trying to find one that didn't have a pink splotch on it (visible with apps like Kindle) and I actually enjoy listening to music from the Z3v.  Plus it's a far better speakerphone.  The fact that it's still on 4.4.4 is not an issue.  I have 5.1 phones and I don't see any real compelling reason to prefer one over the other.  So stick with the Sony.  It's a great phone.  Maybe the new Motos will be better.