I have SW and ESB 1.0, and RotJ 2.7. I’m thinking about replacing SW and eSB with 2.7, what are the differences between them?
Well, SW 1.0 is extremely out of date. Just about everything has been improved dramatically since then. ESB 1.0 isn’t terrible, but 2.0 uses much higher quality sources. The encodings of all the 1.0s are also lower quality (low bitrate, a bit more pixelated).
As for Jedi 2.7, it doesn’t exist which is problematic for comparisons. But Jedi 2.5 is out, and ESB 2.5 will be someday in the hopefully-not-too-distant future.