For all out performance numbers, the Z06 is the better car in stock trim. However, if you are prone to modify your car, you may want to wait and see what new toys the aftermarket will develop for the LS2. Everything that is developed for the new generation SBC (heads, intakes, throttle bodies, etc) will not be compatible with the LS1. Remeber, the LS2 is a throttle by wire car, with revised block features that change the outside dimensions and mounting locations. Finally, it begs the question, which car put the bigger grin on your face. After all, that is what this hobby is about!!
Brett