So James I have heard that maxim's stuff looks amazing, how is the quality? You think I should trust my noggin in ACL combat to his gear?
Well, that's a loaded question! I saw IceFalcon has been trying to get a helmet replaced by Maxim that broke or something, for 6+ months or so. I'd guess it's a carbon steel helmet; I've heard good and bad about heat treated carbon steel armor from the Ukraine, more along the lines of their steel isn't as consistent so even with proper and consistent heat treating methods, they produce the odd piece here and there that will crack.
That said, I don't think I'd trust my noggin in *any* armor for ACL, because no way would I do ACL at all.
I would go with 10 or 12 gauge mild and oversize the helmet to add extra padded. Layer or two of sorbothane on the outside, and horsehair padded on the inside. Mild steel is far less likely to crack; it's going to dent easier than equivalent carbon steel, but they're destroying helmets and armor like a Berserker over there. Even spring stainless, the top tier reasonable metal for armor, seems to get dented and abused.
Granted, it shows that armor REALLY works, because I have no doubt most of those people would be dead if they didn't have armor ... but if you're seriously considering ACL, I'd talk with the guys who do it, and get their opinions. Also, ACL related travel costs will probably be $5k-$10k for a year. One guy who went to BotN last year or the year before did a fundraiser to raise $8k to go to Europe to compete. So the armor is a minor cost, relatively speaking.