The diesel option for the Q5 is still 1 year away. Current additions were the 3.0T replacing the 3.2 and a hybrid. The 3.0T is a great engine and is now just arriving in the states. But if I read it correctly, BMW will also be introducing their diesel engine to the X3 and 3-series wagon.
I don't own a Q5 but my wife has a A4 2.0T and we seriously considered the Q5. While there a many positives, we are leaning toward the X3 28i.