Daniel Defense definitely is worth the extra money - if you need that kind of quality and reliability. As I remember from another thread, you also have a Windham so give it plenty of thought and decide which rifles to sell and which to own. I like the SIG M400 but myself I have DD, BCM and PSA ARs.
Just curious out of the ARs you have and with your real world experience with them. What truly makes the DD stand out and worth more than the others. Can you give some insight on actual things like accuracy, any kind of malfunctions that keep the weapons from firing, stuff like that.