Interesting note if you rely on Photozone Lens reviews

Actually the A77 sensor performs close to the A900 and A99 when the files are well exposed (focal lenght with same angle of view), and just about one stop behind the A900 at high ISO settings, which is excellent for an APS-C camera. What you call "lack of pixel sharpness" probably is the sensor outperforming the lens used, showing optical lens flaws. With excellent glass the A77 pixel sharpness is very high. This camera clearly outresolves the A99 and A900 when the same focal length is used.

The A77 sensor is not bad, but to get the most out of this high resolution camera you need more than excellent glass. You also need skills. A lot of Nikon users have experienced something like this with the D800.