I've actually been able to compare the VX2025WM, 2007WFP, and 20WMGX2 all at the same time and found that the 20WMGX2 was the best monitor to have if you want the best picture.
The ViewSonic was good and much cheaper, but it also had / has some lurking DVI port issues that I just didn't want to mess with. One really nice thing about it is that it is that its panel hardly ever gets dead pixels. After I couldn't find any xtknight filled me in on that little detail. Its picture was pretty solid compared to the other two, but it didn't have a uniform background and had some evident backlight bleeding in the corners - making the black-levels kinda pointless and dark games like FEAR or Q4 not so fun to play.
The Dell had the best bezel / stand out of all of them. If you want your monitor to look pretty good and bend and move in a variety of ways the 2007WFP would be the one for you. That and it has more connectivity than either the VX2025WM or the 20WMGX2. I believe it supports some scaling through the OSD, but I never messed with that when I had them. It had great uniformity with no backlight bleeding, the picture had good colors and the price tag was good. If you're just not sure about the NEC, the 2007WFP would be my second choice.
The NEC has the best picture quality of any LCD I've ever seen. Period. Deep blacklevels, uniform backlight, and a color contrast ratio that stomps the Dell or ViewSonic. It's gives, I think, the best speed per image quality ratio out of the LCD's (Samsung makes a good one that actually has better colors but is slower). The bezel is alright, I'm not a fan of gray but when the picture looks as good as this I don't care. Also the stand is fixed only allows you to tilt the panel forward or backward, so if you want to have a little bit more flexibility the NEC isn't the best choice. It also sports an "Opticlear" coating that either makes or breaks it for some. I do A LOT of my computer stuff in a completely dark room with a keyboard with lighted keys, so a reflective Opticlear coating doesn't bother me as there is no light. Yet my brother hates this monitor simply because of the coating. He doesn't have a lighted keyboard and likes to play with a light on in his room and the coating on this monitor really does give a mirror reflection when there's enough light. It has less conectivity than the Dell and doesn't support scaling in the OSD.
Hope this helps.