i wouldn't write it off because of what Gustavo said. it's not unusual for monitors to have a bias from the factory. some sony sd monitors used to be a little heavy on the green out of the box. Marshall makes perfectly fine monitors, tho they aren't always as feature-rich as some others.
I use one of three different options for viewing my HD material in the field. I will list them, but NOT in ranking order! (I feel obligated to start by saying at one time I owned a 17" Panasonic HD monitor, but it ALWAYS looked green, even after calibrating it! So I was fortunate enough that Band Pro took it back and replaced it with a JVC).
1) JVC 17" HD SDI monitor. This thing has all the inputs you'd ever want, component, composite, SDI (auto sensing). I thought this was the cream of the crop, until I saw monitor number two! I still use this because it has a Porta Brace case built/made/designed for it, with a built in sun shade and it works well outside! It's also AC/DC operable.
2) Sony Luma Series 17" HD monitor. WOW! Is all I can say about the picture! No monitor under the size of 24" is "truly" 1920 x 1080 native. However, even at a smaller pixel size, this thing is amazing! I'd make this my ONLY monitor if someone like Porta Brace, Petrol or Kata made a "run-bag" type monitor case for it that had a built in sun shade and shoulder strap! It is AC/DC operable.
3) Leader 5330. This is the latest toy. It's phenominal! It's not only a 6" monitor, but it's a wave form monitor, vector scope and has some pretty other amazing features designed to help in the field... It can sample two distinctive points in the picture and then give you the difference in their apature ranges! This is great for knowing the dynamic range of your picture. It has a "Zone" metering system that displays exposure in terms of color... similar to Predator, if you've ever seen that movie. And it can give you TRUE RGB values so you know what a composite signal will look like. This one costs more than the rest, but when it's CRITICAL, we reach for this first... more of a calibration and monitoring of tech status than a monitor, but a very good monitor as well!
Picture This Productions
Sony ICE Team
Adobe Premiere Pro CS3 HD/Matrox