I have a dell 2408WFP on my hackintosh
Pros:
~obviously screen real estate is great
~Matte doesnt pick up annoying reflections
~lots of connectors, great for if you want to use your setup for more than just connecting to a computer.
~very good contrast
~cheaper than the ACD
Cons
~Damn this thing is bulky! its bigger than a 24" imac, except it doesnt have a chin. its far bigger than what it needs to be
~feels plasticky, looks alright but it is plasticky, no question about that and the plastic seems to have a lot of flex in it
~Heat, well lets just say you can heat your room with it! It puts out more heat than my mates 20" imac!!!
~Backlight bleed, exists in the top two corners, not really noticible unless you are watching a black screen in a dark room.
~feels like it needs a remote control to take better advantage of the features.
Overall this display gives a very good picture and performs brilliantly but the overall package is let down by cheap plastics, poor space management and poor energy management. This display could be a lot smaller and a lot cooler and wrapped in nicer materials, but that wouldnt be the dell way would it!
the ACD has an IPS panel rather than a PVA panel which is meant to be a slightly better technology for image quality. The ACD offers less connectors and is pretty much only good for using with a macbook unibody (or a new mac pro i think) but it will be much higher quality and as with anything apple, it will be engineered extremely well and that in my opinion is worth paying for if you have the money.