Ram TAC is my go-to powder for 5.56. I can't attest to the AA.
If you mean by smooth measuring that it accurately drops. Yep. I use a Hornady powder drop and there's never any sticking or a slight jam from powder kernels getting cut, crushed, or stuck. Drops clean with no sticking inside the powder drop tube or die.
I vote it's smooth measuring. Burns a hair dirty but I mark that up to a looser crimp.
A good friend of mine who worked for Sierra Bullets told me the best commercially powder available for the 5.56 was Ram Tac powder. Clean burning and measures well. It works well in my AR's.
Both are great powders, deliver great velocity, and meter easily. I prefer 2230 but a lot of guys love TAC. 2230 is Xterminator in the Ramshot lineup IIRC