I was recently forced to try H322 in my AR's because it was the only powder available locally that I could load into my .223's.
I am pleasantly surprised with the results. I get good velocity and accuracy with this powder. Many times it's either great accuracy, or it's great velocity, but not both. The 322 seems to provide both.
I have previously had success with Benchmark, BLC-2, Accurate 2015, and H335. They all seem to shoot well. The 2015 shoots really well and it usually costs a bit less than the others.