That doesn't strike me as much cheaper than a PC monitor of similar spec.
The problem with workstation monitors like this is that they are often fixed-frequency - which means only one resolution and one refresh rate. Anything else cannot be displayed. This is an engineering compromise - the monitor can be tuned to one resolution so can have outstanding quality while at the same time keeping it affordable. The SGI displays are well known for being of excellent quality.
In other words if you set Windows to 1600x1200 at 75Hz it may work fine. But during boot-up you will have a blank screen, similarly if you change the screen res or play a game then the screen will go blank.
If you are certain that it is a multi-scan monitor, then it may be a good buy - as long as it is in good condition.