Day 2 on build 10549 (after it received another configuration update)
1. battery life- pathetic stand by time. slept with the battery having about 55% woke up with about 7% . no background apps, no cortana enabled, wifi off, and cellular data on (edge , due to the poor reception at my residence). however when the device is in use during the day i am getting the same if not similar battery back up as 8.1
2. camera- its the same as 8.1 being a 1020 user i cannot be more happier than having lumia camera back . performance is the same and shot to shot time is the same .
3. Photo gallery app- MUCH MUCH improved and kudos to Microsoft for getting things better. while its still lil laggy while zooming into pics but no minus points for that as its still a technical build and i am assuming its a few builds behind RTM.
4. Email app has been reworked thoroughly and is much more usable , however the lack of combined inbox is still something i sorely miss from 8.1 and the mails take a tad bit longer for it to open up , even if connected to wifi.
5..animations are quite smooth actually and at par with 8.1
6. the infamous "resuming..." screen still is present but much less than the previous build. it usually occurs one out of ten times when the phone is unlocked and even if it does barely lasts a second or two, however that isnt always the case with certain apps like whatsapp as they for still some reason are little laggy even if the phone is on 8.1.