I wouldn't entirely agree with that post.
It is true that Apple's display panels are almost exclusively manufactured by Samsung and LG, but that doesn't make all LCD-LED displays the same.
Some panels offer better color representation and vividity, richer black etc. than others.
The only way to make sure that you're getting the display you want is as I've said above, seeing them for yourself. Refering to on-line benchmarks can be helpful to determine rather the display has good color accuracy, viewing angle, gamma and more since those things are difficult to tell with just your eyes.
To my knowledge Apple's displays tend to have higher contrast, gamma, and saturation in comparison to the 'correct' or '0' values. If you want the color on the display to look exactly as it would when you print it off, Apple display may not be the best solution. But for multimedia and entertainment purposes, they work great.
But the WLED on the thunderbolt displays are great- once they're calibrated, their color profile is a lot more superior than other displays.
I would advise you to look at the benchmarks for yourself.
But I am not exactly debunking the thread from the link you gave me - it does have some truth in there.
For the performance - Apple displays are definitely ripoffs. I'm confident that you can find a deal with similar performance in the $600 level.
The only problem is though - if you don't like the display of the panel, you're going to get annoyed really quickly because you do have to stare at the thing for a few hours at a time.
So you can either chose: A really minimalistic design (Which dell usually offers) that really doesn't impact your experience much, or a really pretty one, like the Apple display, which is pleasant for your eyes during and outside use.