I took a look at DxO's info on three rather different Sony cameras: A6000, a77 and a900.
The A6000 is as good as the a900 in everything but dynamic range, for which it is a full f-stop ahead! So much for the quaint idea that the industry has made little progress in recent years in sensor performance - now we have an $800 Sony APS-C camera with 2009 full-frame performance - a terrific result.
It is also handily better than the a77 which suffers an SLT-induced hit, but is really a low ISO camera.
Sony A6000 versus Sony SLT Alpha 77 versus Sony Alpha 900 - Side by side camera comparison - DxOMark
It's also basically an even match for Nikon's D7100 - a $400 more expensive camera.