I believe somewhere in the immutable laws of photography it is written that the first photographs taken with new gear shall be of a cat, preferably one's own cat. This is my family's kitten and she was the test subject for the first photo with a new (for me) 600mm. Available light at night indoors with a stupid high ISO and what I thought was an impossibly low shutter speed. Kitten is incredibly awesome, the lens almost as great. C & C always welcome.
Danphoto -- Thanks! Hallways are definitely your friend with long minimum focusing distances.
Sauseschritt -- agreed... not a lens test, just a first photo. The 'testing' was the next evening and the weekend at a track meet and soccer game. The lens passed with flying colours.
DanielScott -- Thanks! while not the lightest thing I've ever picked up, it really isn't that heavy. Certainly massively lighter than the previous versions of the lens.