The one thing I can't stand when I see Napoleonic and American Civil War reenactors is the ridiculous difference of uniforms. I understand that it's different groups together, but seriously... You have 4 fusiliers, with 20 linemen, with 6 grenadiers, all in different color uniforms, militia thrown in there too. I know it's a pride thing, but i think if people would join each other, actually take the time to get correct gear, and look like a real unit of soldiers, whether it be half a company of 50 guys, or a full company of 100, would just be fucking awesome. That's what deterred me from Napoleonic and ACW. In WW1 and later, units are smaller, so you have an excuse to say, "my 10 guys is all we need!"
That's still a fucking awesome .gif to see people marching in perfect unison. I'm sure that must have taken a long time to get correct.