Don’t buy Samsung old devices because they stop supporting there devices after I or max 2 year.For example currently I’m using note 3 and note 3 haven’t received lolipop 5.0.1 that means note 3 the flagship phone of Samsung is 3 version behind "5.0.1" "5.1.1" "6.0.3"
Now the drawback as I’m on 5.0.0 lolipop and I want to use a app(lets suppose autometa) and it requires 5.1 but you can’t use it because our device is not updated .so long story short go for Samsung’s new devices if you are Samsung fan else go foe nexus if you want to really enjoy the android.Nexus is Google Product and it receive updates as soon as google launches .no delay no bug.
Thanks