I also still own the original 4 disc set but haven't installed and played it for quite a while so I honestly don't know if it's difficult getting the original version to run on Windows 7, 8.1 or 10. Right now I'm on vacation so I don't have access to my original discs or my new desktop pc so I'm unable to test the original version.

But I can confirm that the GOG.com version will run on Windows 10 out of the box. I did have a problem with the in game photo album where photo's now get displayed behind the layout instead of in front rendering the built in camera useless. But this is a known problem and unfortunately something that probably won't get fixed. So I guess I'll just take screenshots using my smart phone (an option I didn't have back then). This problem will probably also manifest itself when using the original discs so that's not a reason to avoid the GOG.com release.

But the main reason to get this version (for me at least) is because it allows me to play the game on my netbook (which doesn't have a physical drive) and I won't have to swap discs or worry about my discs getting scratched or lost.

In other words: if you can install and run this game without any problems from the original discs on your current Windows version and you don't mind having to swap discs, then no, this version is not an improvement. If you need to fiddle with compatibility options or need to use Virtual PC to get the game to run from the original discs then yes, this version is an improvement since it will run on modern Windows versions right after installation.