I also owned the Colt M4 for just one day. It was a display model (last one) at a local sportsmans store, and I was concerned that it had been "handled" a lot. Normally this chain does not allow firearm returns, but since I argued and tried to beat them up on the price, which they wouldn't do, the boy told me (and I got it in writing) that if there was anything wrong with it, I could return it for a full refund. I got it home, loaded up a mag, worked the action to charge the round. Removed the clip and tried to open the action to remove the live round. Guess what?...it didn't come out. The ejecter was jacked up, likely from being "handled" in the store, but if it can't stand up to store handling, it likely wouldn't have stood up to my use. I took it back, got my refund, and bought the M&P 15-22 and never looked back. Since then, I've learned about the pencil barrel and all the proprietary parts on the Colt. It looks nice, and it's heavy...but that's it. Glad I have the S&W. I've put almost 1500 rounds thru mine, and love it. I normally do not try to recommend or not recommend any particular product...but really, Colt (Umarex) tried to do a good job to make an imitation AR-15, which they did a fine job as far as looks go. If you are after a wall hanger, get the Colt. If you want one to shoot...get the M&P15-22!