yotsuya said:

I had heard they were from the same master tape, but the NTSC disc that I ripped has black bars on the left and right sides and the PAL disc does not. Also, the PAL letterbox crops the image slightly smaller top and bottom.

From what I recall, the PAL discs were actually created from NTSC masters (except for RoTJ?). There seems to be a consensus that the NTSC SW and ESB are superior, hence their use here. RoTJ is either debatable or if anyone ever settled it I don't remember the outcome. Or both are too terrible to even be worth discussing? :)