I've seen some stuff suggesting that the panels in the old 20'' iMacs were better than the new ones, but is there actually any reason to believe that the 24'' aluminum iMac doesn't use the exact same panels as its predecessor..?
The new 24" iMac's panel has the same base part number as the previous model, but with a different suffix:
White C2D 24" .... LG.Philips LM240WU2-SLA1, 8-bit, S-IPS
Aluminum 24" ...... LG.Philips LM240WU2-SLB1, 8-bit, S-IPS
I presume that the base part number identifies the actual TFT panel, but the different suffixes could mean almost anything --
maybe just gloss vs. matte finish on the panel face, or
maybe an entirely different backlight/diffuser/inverter assembly and/or a different grade of parts from the manufacturer's quality-inspection sort. I'll betcha a nickel that the old panel is too thick to fit in the new aluminum cabinet.
Of course, in the final analysis, part numbers make no difference; it's the end result that counts -- and light meters don't lie. Every ALU 24" that I've seen and/or measured had incredibly poor luminance uniformity -- 2.5:1 or worse.
OTOH, there's absolutely no doubt about the 20" ALU displays; the new product is a cost-driven major downgrade. In this case, the part numbers, light meter readings, and visual inspection all agree -- it's a disgraceful POS, far worse than any other TN panel I've seen. The glossy glass cover is just lipstick on a pig.
White C2D 20" .... Samsung LTM201M1, 8-bit, S-PVA
Aluminum 20" ...... LG.Philips LM201WE3,
6-bit, TN Film
...a thing of beauty is a joy forever,
LK