Things I liked:The Walther CP99 is a very close copy to the P99 9mm, both in weight and design. You get a really good feeling shooting this because it feels like you are holding a serious, well made gun. Umarex did a great job with this as usual. The ability to shoot either single or double action is a great feature and this gun does not leak CO2 at all, I have had it sit for a week and when I took it out to shoot, it was still full. Things I would have changed:It would be awsome if they made this one with blowback, I have the bb version which features this but I like pellet pistols better. What others should know:If you are going to buy an air pistol and can afford to spend a little extra, this gun is worth every penny. It will last you a long time and the quality really adds to the amount of fun you will have shooting it. I am a huge fan of Walther and own several of their real pistols, the CP99 looks great next to my P99 9mm.