It's hard to compare these with the original graphics or the high quality replacements created by the community over the years. They're not really better or worse, but they're certainly a different way to experience the game.
Highly recommended you try them out if have the required hardware. I'm planning on doing a complete play through of M2.
These files will allow you to extract and implement all HD sprites and textures from the XBox Live Arcade version of Marathon:Durandal into your AlephOne installation of Marathon 2.
Detailed instructions on how to get it working can be found in the included ReadMe file.
This was made possible thanks to the combined efforts of Treellama and thedoctor45.
Hope you enjoy.