Things I liked:I like the compact design of this rifle and all the rail space. With a red dot attached the accuracy is very good. Very easy to field strip. Follows the same platform as the M4A1. I like the rubber butt pad on the butt stock. Much more comfortable than the plastic six position stock found on the M4A1. Metal flash hider instead of plastic, very nice. Blow back provides a strong kick with the recoil. Things I would have changed:The return spring attached to the bolt assembly does not use a guide rod. You need a special tool to unhook it. I'm a little concerned the spring might break. Wish the magazines had a 50 round capacity instead of 30 rounds. Magazines are prone to leak. What others should know:Be very careful when loading the magazines with gas. Do not over fill and you will less likely have leaks. Leave a little bit of green gas in the magazine, enough for 3 shots to keep the O rings lubricated. After shooting on full auto all the magazine to return to room temperature before using again.