I use Barnaul and Czech surplus pretty much exclusively. Ballistics as close to identical as doesn't count. I use the Czech when I'm planning on really burning through a pile (cost) and the Barnaul on days when I know I might not have a chance to clean within 24 hours. Really good stuff.
I also recently saw a vid on why you have to worry less about steel cased ammo with 7.62x39 as opposed to .223/556 NATO. It has to do with 7.62x39 having a slightly deeper and wider groove at the base for the ejector to grab hold of, which makes for a more solid purchase to overcome the slightly stiffer case extraction. Lacquered cases are as "slick" as brass, but because they deform less easily, they press up against the chamber somewhat more. Also, 7.62x39 is slightly tapered whereas 5.56 NATO is not, so as soon as the case is drawn even slightly back it is disengaged from the chamber wall, whereas 5.56 NATO's straight cylindrical design means that it is in contact with the chamber wall until it is fully extracted.
I should have bookmarked it. It was an elegant explanation of something I'd wondered about, and explains why the East Block has stuck with steel cased ammo (cheaper) and yet their weapons still have such an excellent reputation for reliability.