I agree that the cleanup was well done. And I like the 97SE colors for the most part.

The optical effects cleanup was mostly so that the film could be restored from the negatives, but I think they look fine and don't care at all about the frame-by-frame accuracy of them (aside from syncing to GOUT, of course). I actually really like the things that were recomposited from original elements and/or had their transparency issues and matte lines/boxes fixed. Those things belong in preservations, sure, but I definitely see the changes as improvements. Not really a fan of the added blur effects in some cases.

Tough to choose between least bad SE for the first two films. For ANH, Jabba gets slightly less terrible as time goes on, as does the Greedo shot and the green lightsaber. But the soundtrack sucks in 04 and there are the rocks in 11. Plus, the color.

ESB really only has the falling scream issue in 97. Changes after that were minor, but for the worse. I actually just watched the 2004 version. The SE is much more intact and watchable than ANH/Jedi. The cloud city CGI looks bad in a couple shots, though.

Jedi had relatively few changes, but Jedi Rocks and the Sarlacc beak were really awful. In this case, I think every change post-1997 made it worse. So, 1997 was easily the least awful.