I'm not surprised. Demand is high for the new iMacs. A lot of people on MacRumors want to complain that Apple isn't meeting their current 'buying criteria' of more power but the truth of the matter is Apple Inc. is filled with smart minds that know society changes, and so does 'buying criteria.'
Not only are iMac's more powerful, but they are thinner, lighter, simpler and more essentialwhich is what society wants in a desktop machine going forward. Our buying criteria is more influenced by laptops and tablets than anything else.
I talk about buying criteria in my latest podcast. if you want to learn about it and how businesses use it as an innovation strategy.
They are very nice, but still date themselves by not having some sort of upgradable graphics card slot or something. I can't drop $2500+ on a desktop that will be dated in 2 years in terms of the graphics card for doing my graphic/motion graphics on.
At least the laptops are portable. But for a desktop, there needs to be upgradability in the GPU chip somehow (and they need to design it that way)