The "Before the AI version" spoiler in the OG post is an old, yet most stable version of the game (V5.8b) where it has the usual 4:3 ratio of RPGM games
The current version (V6.8) is a wide-screen (16:8) version of the game with high quality scenes and naturally more content + scenes but with some bugs. Not gamebreaking. But annoying if you know how to handle em. Most of them got fixed this version.
The difference is that if you tried directly replacing the scenes from V5.8b to the current version. The scene would appear to be sooo small due to the file resolution.
As for which version is better......
That strongly depends on your taste and preferences in the scenes. I personally prefer some of both AI and handrawn. Or if you don't care about the new content and don't mind the 4:3 aspect ratio.
As for the AI scenes...MOST of them got replaced by the hand-drawn art from V5.8b in V6.8
As for the rest of the AI'd scenes that hasn't been replaced. You can just open www/pictures and review the AI'd scenes and decide whether to replace or keep them..
You can find and download the non-AI'd scenes Upscaled to 16:8 widescreen post
here.
There's also another one here where the old, hand-drawn images from 5.8b, upscaled while maintaining original height/width proportion (4:3)
here.