What happens when you plug a console into a 16:10 monitor? Is it shockingly bad?
Depends if it has a 1:1 pixel mapping option. Monitors with 1:1 run 16:9 resolutions with black bars top and bottom and the correct aspect ratio.
The U2412M doesn't so you need to pick a 16:10 resolution to start with. The highest one on the 360 via VGA is 1680x1050. There is a 1920x1080 option, but that stretches the image vertically to fill the panel.