I have written replies to this very question several times. I would suggest the search feature.
that said, here is my previous post ---
As a user of a Dual 23" Apple display setup I feel I should input my view.
The Apple 23" is an extremely nice monitor. Its major benefits are the Aluminum casing and the sleek sturdy design. The monitor itself does have a very high dot pitch, and is very clear. However, I won't kid you, the 23" Apple has some real problems.
First, it is known to cast a pink hue, something I have dealt with on both of my displays. I even had to send one of my displays in to Apple 4 times until they replaced it with a new product. Even once they did that I can still not calibrate my monitors to be perfect. Second, they only have one plug in, no Svideo, and no multi DVI plugs. Due to this the DVI cable is permanently attached, therefore, if it ever needs replacing it would be extremely expensive. Last, the color contrast across the screen is not accurate. On some parts of the displays contrast is perfect but on the sides it starts to wash out. I don't know how other high end monitors handle this, but it can be annoying if you are dealing with a program such as itunes. This is because itunes has a very minute color difference from one row to the next.
I used to own Viewsonic 17" pro monitors, each one was beautiful as far as the screen, but the casing was a cheap plastic that became very frustrating.
I found that the monitors would constantly wobble, and due to their rotation capabilities they had even more problems. When I started to look into new displays I wanted something that was sturdy and very solid. This is where the Apple monitor really shines. The casing is beautiful but is also very elegant and sturdy. My displays never wobble, and they are constantly perfectly positioned next to each other. Besides this the touch buttons are a great way to control the monitors. The Apple display really had a great feel to it.
Overall, I would have to say that if you are looking specifically for 23" or 24" that you should avoid the Apple if you want great color consistency and don't want a high price. However, if you are flexible, the Apple 20" and 30" are absolutely stunning and still have the benefits of the Apple casing and look.
I hope this helps in your decision.