got 4.4.2 on my Telecom handset, Telecom SIM. im also finding this update running smooth with no problems mentioned above.
today as an example, was at a all day conference so checking work emails all day, photographs, twitter feed updates almost all morning/afternoon - some browsing and videos this evening (reading up on the making of 'MONSTERS' 2010 movie from the director of the latest Godzilla - astounding film for effectively a one-man production) so you can see the 'awake' times being pretty consistent all day, never really gave the phone a break.
almost 5 hours screen on time for whole day is not bad to get to almost empty. using a LightGrid livewallpaper as well which is constantly animating that grid of squares you see on the homescreen. usually i only average about 2.5hrs screen on time per day and that results in about 60% battery remaining by the time it goes on charge at bedtime
for a stock unrooted ROM i think thats reasonable performance - i can see that the claimed 8hrs screen time on the rooted optimised ROMS would be easily achievable.



