At this point more and more information on the new EV3 platform are coming to the market, we love to see all the videos form CES 2013, here are some sites, for more details.
Robotsquare: EV3 31313 sensor and motors picture
Botbench: Compare the NXT to the EV3
Roberta: a PDF in German and a PDF in English with a good side by side comparison.
LEGO Education also put a comparison fact sheet up.