Piracy has evolved so much in recent years, People who manufacture these pirated products are able to do made very well copies of successful phones like the Samsung Galaxy Note 4! Below are some tips to avoid these phones:
Hardware: The hardware of these pirated products are dated.
Apps: In the case of Samsung, you will not find the traditional apps brand.
Software: Android is normally an older version like 3.0 Horney Comb, 4.0 Ice Cream Sandwiche or 4.4 Kit Kat. In the case of Apple products, the interface is the same as the IOS but when the "App Store" is executed, you will be faced with the Google Play.
in the image, you can see the white color with the original Samsung Galaxy S5 and the Pirate phone with yellow color. It is hard to see the diference.