ahhhhh! Stop the war of Dell vs. ACD...!!
To each their own. It will depend on the user's needs and income as to whether the ACD is worth it. For me, the ACD is a rip off, and not at all worth its price tag compared to what else it out there. I'm a college kid on a college kid's budget, and not doing anything that would even come CLOSE to challenging the differences between the Dell display and Apple's.
But others might (will!) disagree, others might have needs that the ACD can only satisfy, others might follow Apple blindly, and others might just have so much money that they couldn't care less. Does it matter? No. You earn your money, I earn mine, and we all can choose what to do with it.
As long as everyone is happy with their own setup, that should be enough.