I'm not a fan of things that attempt to "improve" older graphics*. I feel that SuperEagle, SAI, etc. do more to detract than add to the image. However when it comes to recreating accurately what we used to see on CRT monitors -- that's actually taking the experience closer to how the game looked... and it arguably looks better, too.
Probably really complicated, though!
* - With the exception of Laserschwert's AI upscales of Curse of Monkey Island, which need to find their way into a version of that game at some point!