definitely redmi note 4. u can install custom rom based on android nougat like lineage, aosp or resurrection remix and it will ran as good as high spec phone.

make sure u install minimum gapps.

if possible get the SD

honestly
if u can afford more. i suggest get a faster android phone ... else u will feel android not as smooth as iphone

maybe one plus 3t is better suited for ur speed and price
around 133 per month on lazada

Keep your iphone 6s. use until you finish the loan. or until it breaks.

I have friends that use Samsung low end phone (RM700 ), complain lag lah , this no good that no good.

Then go buy a 2k plus Iphone ( because iphone dont have low tier phone during iphone 4s/5 days),
say iphone very good, basicly because they are comparing a 2k plus phone with a RM700 phone.

I dont want you to change from IP6s to Xiaomi and make generalization that "Android ( MIUI )not human use one" . 

I ALREADY DID NO 1
and never regret it.

i rather use my rn3pro vs rn4 3gb ram coz im gaming abit too

Performance camera wise. Get the mi5s
Only get the rn4 if u don't need extra speed and need that big storage and battery.

Else I keep my Rn3pro 32gb

The redmi note 3 is faster but has about 30% less battery life

You decide performance + save money or battery life

Mi5 dun talk lah. Stupid battery life but again very fast.

To put into context

Mi5s  4 to 5 hour screen on time - best performance CPU - some heating issue - rm1xxx

Redmi note 3 6-8 screen on time - mid range cpu - get very warm when playing intense games - rm6xx for 3/32 (max spec btw)

Redmi note 4 8-12 screen on time - lower mid range - barely warm when playing intense games - rm8xx for 4/64

You decide

I would rather wait for Redmi Note 5 tbh because it will have redmi note 4 battery life and redmi note 3 (even better) performance