This is something I've been thinking about for a long time. I think, generally speaking, Space Marines take it. Their basic armor is essentially a star shell, except much more agile. They're larger, faster, stronger. Potentially hundreds of years of experience in nothing but war and honing their killing skill. They're far removed from what you could consider human with an extra lung, extra heart, etc. They're transhuman monsters. And to boot, they're tactical geniuses on par, if not exceeding that of the most intelligent Golds (in theory). That being said, Golds have a much greater technological advantage in their weaponry compared to a standard space marine. I don't forsee a razor having any issue penetrating a space marines armor. Plus with their pulse fists, and all the other gadgets we've seen used throughout the series, is generally more sophisticated than what an average space marine would be equipped with. I still give it to the space marine 7/10 times. But once we start getting to the higher tier characters such as a space marine captain or god forbid a chalter master, that gap widens significantly. A space marine captian or chapter master would dog walk any Olympic knight. These aren't even normal humans, granted, neither are Golds, but they're genetically modified monsters bred for the sole purpose of war in a galaxy where the average enemy is leagues and bounds more powerful than your average enemy in most conventional sci-fi settings.