What is the difference between the Nexus 7 screen and Kindle Fire HD7 screen?

Okay, so today on the vergecast, both Nilay and Josh seemed to agree that the Kindle Fire HD7's screen was better than the Nexus 7's screen, even though they're both IPS LCS's with the same screen resolution. How do they figure that?

Did anybody read something somewhere that mentions that the Kindle Fire HD7 has a better screen?