When it comes to BTUs, gassers can't touch a good charcoal grill. Set your Weber kettle up with hot and "cool" sides, and you can make an awesome steak. Use less charcoal and adjust your airflow down for chicken. Set up for indirect cooking, and you can smoke food in it.
You don't need to season the grill, but on your first cook, I would get the temperature up and let any funk from manufacturing burn off before putting meat on it.
I suggest you take your CI grates off the cooker after they cool, and store them inside. Mine rusted pretty easily if I left them outside with the grill. I hang all my grates on the wall in my garage, and that has worked well for me.