I'm not particularly impressed with Dell's displays, but they're not bad, and they do tend to be cheap (that is Dell's specialty, after all).
It's interesting to note that if you look at the actual performance graphs that go with that review (for example, the one at the bottom of the top-rated-in-that-review
Planar monitor, which shows the Dell and Apple displays as well), you'll notice that the Apple display is far and away brighter than any of the competing monitors, and bests everything but the Planar monitor in whatever their general quality test is.
Basically, you generally get what you pay for. The Dell is cheap, and it'll no doubt get the job done if you're not a quality fanatic, but it's not of the same calibre as a monitor that costs a few hundred dollars more. And that Planar is more expensive than the Apple monitor, despite being very nearly of the same performance grade and much brighter at the top end.
I do agree that Apple's monitors can really use an upgrade at some point here, but they're still being reviewed quite well against the competition in everything except price and support. They were just so far out ahead to start with that it's taken almost this long for the rest of the industry to catch up.
(*caveat: I know Apple doesn't make it's LCD screens, but the companies that do usually charge WAY more for the same panel in a different frame; I recently saw monitors using the same panel as the 20" Apple display selling for nearly $2000.)