Are you sure the Eizo FS2332 is only around $100 more than the Dell U2312? The Eizo FS2332 typically sells for $500 - $600. The Eizo FS2332 uses a H-IPS LCD panel while the Dell u2312 use the less expensive e-IPS panel.
I too prefer a monitor with adjustable height, but at least the Eizo can accept a VESA mount compatible so you can add a height adjustable stand later. The main problem I have with the Eizo is that you need the remote to access the OSD menu. The monitor itself does not have a button you can simply push to get to the monitor's menu. So if you loose the remote or it breaks then you need to buy a replacement from Eizo to access the menu.
Other than the remote control issue, I would likely buy the Eizo over the Dell if the price difference is really only around $100 more.
The grainy / dirty image is actually due to the anti glare coating. Since both monitors have matte finishes, they both have an anti glare coating. Therefore, images on the Eizo may appear "dirty" as well. Generally speaking, the thicker the AG coating, the more "dirty" images can look.