EDIT: I found that cell standby abnormal usage is not only on this phone.,also.in any kitkat devices,and there's a fix
(i'm yet allowed to post link) Just google search japanmobiletech fix kitkat excessive cell standby
i can't yet confirmed this,not having access to a computer right now
Jelly bean 4.3 to me, make my phone last longer than kitkat 4.4.4, while 4.3 have problem in com.sonyericsson.wakeup usage(there is a simple fix)
4.4.4 have problem in cell standby, android os, phone idle,android system,google play services usage.
(NOTE THIS:But after greenifying app(facebook) and preventing wakelocks (mostly google related) and disabling apps(google+,hangouts)
,apparently, (note this!) cell standby is the real problem in kitkat 4.4.4. Yesterday i activate airplane mode and i slept over 6 hours,the battery percentage is not decreasing at all! without any/stamina/low powet mode on! But this morning, i fully charged my phone then let standby for about 3 hours. Guess what? It decreases to 98% from 100%! And i'm currently searching a fix for cell standby abnormal usage(note that i didnt even make a call or any sms, only wifi,and never without a signal)
Conclusion: i think for light user didnt update from 4.3 to 4.4.4 yet, don't ,there's a battery problem in 4.4.4 phone standbying/idling but what's odd the battery life performance screen on is much better in 4.4.4 than 4.3 so for heavy user , you will notice (it's almost screen 10%/hour screen on!! How cool is that?!?!), and there is a camera improvement in 4.4.4!, it's not big but very noticeable change, definitely make your images looks better, less noise, more accurate colors and there is improvement too in low light condition,
Here some screenshot of battery usage,gsam battery, wakelock, battery stats from full.charge this morning.
This without location, nfc,mobile data,bluetooth,stamina mode,low power mode
Note this: i start using the screen phone at 98% battery level not 100% because of the cell standby drain