R1 or R3 are regional encoding. Which means a R1 DVD (Destined for USA/Canada) is not going to play on a R3 DVD Player. R3 is South East Asia, Hongkong, South Korea.
No guarantee that R1 will be better than R3 in terms of pic quality. Most of the time, it's similar, but refers to individual observations as posted in the forums. Sometime R1 will trumps R3, sometimes the other way around.
R1 has a higher resale value since most R3 DVD get discounted big time a few months after release.
You would need a Region-Free DVD Player to play R1 discs.