[dexmus]

http://www.dxomark.com/index.php/en/Our-publications/DxOMark-reviews/DxOMark-review-for-APS-C-camera-2010-who-takes-the-lead

Have you seen this article? I like dxo articles because they are always to the point, and focused on sensor capabilities. This one compares all new APS-C sensors, and compares back to the old full frame cameras.

Some quotes from the article -

"Dynamic Range: K5 rules!"

"Among today’s new APS-G generation, the K5 is certainly a solid choice, along with the D7000 and the A580, although the Sony Alpha model does not have such an impressive dynamic range compared to the other two at low ISO speeds. All three sensors have solid color depth and good low-light behavior, too. Choosing one among them will certainly be influenced by considerations other than the pure image quality, which for all three of them is very good. "

Case Study: D90 vs D7000 vs D700: Are new APS-C sensors better than the previous generation and better than “old” full-frame sensors?

The improvements are important. Are they enough to close the gap with the “old” full frame sensors? Not yet. Even though the dynamics are better on the new APS-C sensors, and even though the color depth for both sensors is the same, the high ISO score is still far better on an old full-frame sensor such as that of the D700. The score is more than doubled on the D700, meaning that the difference is superior to 1 stop — quite noticeable. This tendency is confirmed by a closer examination of the SNR metrics, the D700 being ahead by almost 4 dB along the entire ISO range.
For a photographer, a full-frame choice is still the best choice for less noise, and without any competition when the ISO has to be raised.