Different Region Explanation
The different region signify where the game is being made for.
R1 = US | R2 = Europe | R3 = Asia (SG/Msia/HK/Korea/Jap) | R4 = Australia & Oceania

There is no difference in the gameplay. However, different regions may or may not have the same:
Box Art | Downloadable Contents (DLC) | Voiceovers & Subtitles | Online Servers | Pricing

Conclusion

If you do not play online or just want to play the game itself, region does not matter. Just buy the cheapest version!
If you have preference between DLC/Cover/Languages, please do more research as it varies from game to game!

source -
http://www.impulse.com.my/playstation/ps4-...limit=50&page=5

this is simple explanation to understand...
for me..i am prefer r3 because my primary account is r3..easy to buy dlc(new clothes,character..etc)as most dlc doesn't work with different region.