realised you are from georgetown, any idea where in penang can i get good deal on the phone?

I always use +2.

Brighten up at low light condition? Low light condition shall dim down the screen not brighten up.

Only brighten up in high light condition, example under sun exposed.

Because I find under 0 kind of dark in certain situation thus I increase +2 and result out suite my need. Shall be consume more battery but not a lot differences, at least I didn't notice the differences on battery usage.

For debloat, you must root, I never do that, so I can't answer you which to remove.

rahuldave try turn off the apps from the application manager. hope this helps. its not debloat totally but at least it won't be running in background or showing up in apps drawer or being asked to update whenever there is in google play.

Bro..b4 u root..try to just disable apps first like what i did..see images above..i disable alot of unused apps until my note 4 damn simple dy

Personally I find it not worth to switch unless the increment needed is merely RM100-200! The current pricing is way over excessive
Phone performs exactly as Note4 n only advantage ( if one see it as advantage) is the added edge

Huhu my Amazon goodies for my Note 4 are here.

Order directly from Amazon and at the same time already registered with Ezipoz so they will give you the US address.
Once Amazon shipped out to the US address the Ezipoz will notify you once they received it and pay the shipping fee plus add the Malaysia address.
More info
The reason I choose Amazon is because to avoid fake or clone products.