Oppo f1s is a good phone and as per according to the price it is valuable and its USP is its camera quality in bright as well as in dim light and rest all the functions are same as in other oppo handsets.
Some of the functions are updated that is:
A) it processor is mediatek MT6755.
B) it has active voice cancellation with dedicated mic
C) colorOS V3.0.0i
D) front camera 16MP 1/3.1 sensor size
E) it has increased its battery to 3075 mah non removable battery.
At the end its a good phone with optimum features.