R1 – USA and Canada
R2 – Europe and Japan
R3 – Asia
R4 – Australia/New Zealand
1. Lanuguage (Manuals and Front or Back Cover)
The first thing that you will notice with the difference in Region are the language used in the manuals and front/back cover. If you do not care about reading the manuals then the region does not matter.
Since different countries have different ratings for video games, PS3 games in some regions may have less gore factor or less blood.
3. TV Signals
R1 and R3 uses NTSC
R2 and R4 uses PAL
This will matter only if you are still using old Television Sets which uses SDTV connections. If you are using new HDTV with HDMI or DVI connections, it does not matter what region you use.
4. DLC (Downloadable Content)
If you plan to download expanded content for your game, then this is important, this also depends on which country did you choose on your PSN account. If you chose USA as your country in your PSN account then you need to load your PSN account using a US PSN Card or using a US-issued Credit Card.