Jean-Marie Sépulchre made a test of the Sony 70-400 mm f/4-5.6 G SSM on a Sony Alpha 900 (24 MP Full frame camera). As this is a serious chunk of nice glass impatiently awaited by many (incl. wildlife photogrpahers like me), it was worth seeing.
The 70-400mm lens test draws the interesting conclusion that “this large very well-built telezoom lens provides high-quality images, and the slight decrease in definition above 300 mm will be compensated by a slight accentuation increase.” JM Sépulchre also points to the serious competition that the 70-300 mm f/4.5-5.6 gives it from inside the Sony lens range, for 30% less money.