Disadvantages:
Non removable battery, come on, we all out of battery and also over time, batteries lose their capacity hence, removable battery is a must these days.
The front camera is ok, its not very good. It really needs to be improved. There are some phones which do better in front camera at the same price point.
The charger is type c which is crazy, you lose the wire, and you will have to pay up a lot of your wallet money to get one more. Accessories for it are also not that readily available, whichever is there is very costly.
No white color available!
Its heavier than oneplus one
No quick charging, the battery takes a while to charge.
No memory card slot, you lose out on the portability of giving your entire data to your friend in a memory card for him to copy it and give you back which used to save a lot of time.
S5 is water and dustproof while this is not.
The finger print sensor is just a sensor, not a button!