In truth, I don't think there is a lot of difference between any of the big AR manufacturers... in fact, DPMS and Bushmaster are partner companies with Remington - they are all owned by the same company. (DPMS makes the R25 for Remington).
In the end, it's all going to boil down to what you like...I've got ARs in 18", 20" and 24" and have used them all as calling rifles (though the 24" get the nod most of the time) They all have RRA 2 stage National Match triggers, but thats what I like...
I shoot Stag, Bushmaster and DPMS, my Cousin owns a Rock River, another Friend owns a Remington...they are all shooters. I'm convinced you could take them all apart, throw the parts into a big pile and put something together that would shoot well.
In short...it would be safe for you to pick either one and go hunting....