We would need the exact models or links would be best to compare apples to apples . I've noticed DD to have more upgrades on there rifles come as standard free float rail better stock nice trigger etc . that brings there price up and with out knowing what models you are comparing to each other it's hard to say what's a good deal for the money .
All the manufacturers you just mentioned make great rifles and you will not go wrong with any of them . I will say again that I would not spend 1k on a standard AR with standard M4 stock handgaurds and trigger . You can find those for $900 and less all day long .
As of this date 8-18-14 at 6:42am I became a proud grandfather I guess I'm officially old
I hear Glock just came out with a new pistol . I hear it's a tribute to the senate and the house of representatives . It's called the congressman . It hardly ever works and can't be fired .