Things I liked:I can't say enough good about this gun! I have the .177 CO2. I have other air rifles but this one has shown me that I really can shoot. It is very accurate!! Very easy to shoot. Things I would have changed:Find a way to cover the CO2 tank with an insulating material like a foam sleeve so that it doesn't feel so cold on my cheek. Find a way to put a shoulder bracket on it as on the air tank version. What others should know:Get a spare, pre-filled tank when you order. They're pretty affordable. You'll be able to continue shooting while waiting for a re-fill.