Here is my opinion. Get the rifle you want right from the get go.
By that I mean if you want rails and collapsable stock and a match trigger ( Save up and get this as the stock one is a disaster), order it that way. Your take offs will be useless and you have paid for them.
I have a DPMS, it has been fine. I have no desire to take it to Iraqistan, I'm not now and never will be a sho' nuff operator nor do I expect to play one on the interwebs, I am not now nor will ever be the Po Po. I don't really believe the world is about to go up in flames, with rioting in the streets ( I live in "Mayberry", Mn.), and if it does am not so naive as to think I can stand off a riot armed with an AR-15.
I have one because they are a hoot to shoot. If I am wrong about all of the above well then I have a good start. I also have the extra $1000 to buy ammo with.