The anti-glare coating on the Dell U2711 is indeed problematic. Anti-glare coatings are used on a lot of screens, the majority of them in fact. Most professional grade monitors intended for high-end graphics use, such as for photographic editing, video editing, etc. usually have an anti-glare coating of some kind, although a few are glossy (no anti-glare/anti-reflection coating.)
The Dell U2711 has a high pixel density, and is apparently a very bright display. High brightness displays and glossy coatings don't generally go all that well together, and result in strong reflections. As such, most screens that are 27" 2560x1440 use some kind of coating to reduce the amount of glare from windows or light sources and reflection of objects in front of the screen (including the user). A notable exception to this rule is the Apple 27" 2560x1440 CinemaDisplay, which is glossy...and comes with all the problems associated with lacking any kind of anti-reflective coating for such a bright, high pixel density screen. It, too, is often downgraded for professional or photographic use unless you are lucky enough to have a very dull setting away from windows or other light sources that could potentially reflect on the screen during use. The older Apple CinemaDisplay 30" also had a slightly problematic anti-reflective coating that exhibited (although much more subtly) some of the same things the Dell U2711 coating does.
The problem with the Dell U2711 is the type of coating. Not all anti-glare coatings are equivalent, and there are a number of approaches one may take to reduce glare. In the case of this Dell screen, which uses "Anti Glare H3 Coating" (according to Dell), the coating is very prismatic, or results in visible refraction and even splitting of light into its component colors. This apparently leads to visible degradation in the quality of the image displayed on the screen, do a degree that most professional users dislike it greatly.
From what I've gathered in my own research of screens in my search to replace the older Apple 30" CinemaDisplay I currently own, the anti-glare coating used by Dell is really designed for screens with a larger pixel pitch. The prismatic nature of the coating works much better with smaller displays with larger pixels, or similarly sized displays of lower resolution. It seems that it is simply the combination of this coating with the particular pixel pitch of the U2711 that actually causes a problem.
If you are looking for a quality professional-grade screen that offers a wide gamut, quality color reproduction, and an appropriate anti-glare coating for the same pixel pitch, I recommend looking into the NEC PA271w-bk. It too is a 27" 2560x1440 screen, however it gets higher marks, sometimes much higher marks, in almost every respect. It also comes with a special calibration system that is explicitly designed to calibrate the PA271 and produce the best results. You will spend a little more on the NEC. List prices are about $950 for the Dell and $1400 for the NEC, however sale prices for the NEC reach as low as $950, vs. about $780 for the Dell. If you pick up the calibration kit along with the screen, you should expect to spend another $100, but it is definitely worth it (you can use other calibration devices with the NEC, however the one explicitly intended to be used with it does a much better, more accurate, and more consistent job according to my research.)