I and 6 other people from Monachium went to Sotahuuto (www.sotahuuto.fi) to check out what the crazy Finns were up to. For only 5M people to draw on for combatants, they have a sizeable event of 600 people (equivalent populace:fighter ratio for the US would yield 35,000 people!). Their rules are somewhat similar (see English translation at http://forum.sotahuuto.fi/viewtopic.php?f=224&t=8219), the biggest differences being head-shots are allowed, touch-hits count, and shields cannot be broken.
A short characterization would be that this is a stick-jock event. There's more of a sports event feel to it than all Belehir (Dagorath?) events I've been to: There are no garb requirements outside of a team surcoat, there are points scored for reaching goals, # survivors, noticably good performance/behaviour, combats are started and stopped by megaphone, common food arranged rather than individual campfires, and not that much evening socializing.
It's quite well organized - the team that took us in actually took a bus there, and as mentioned there's common food service (quite good for the price) and battles are started and ended clearly. The first day's battles started at 9:00, and there was about 8 hours battle the first day and 6 the second day.
The castle battles were the best I've tried: The fort was atop a hill ¾ surrounded by forest, haybale walls with a (dry) moat. Haybales could be removed (by hand).
The swords are less safe - I broke two straight through the core, and I'm not a particularly hard hitter by Belegarth standards. For historical reasons, they don't allow fiberglass cores.
Their spears are very very long, up to 15 feet. They make them in up to three parts for transportaion.
The combination of unbreakable shields and long spears makes for fairly static fronts and less close combat. Helmets are pretty much necessary due to head shots. Them things are warm! Non-reusable missile weapons made development of usable quivers and javelin holders necessary.
Foam covers on arrow nocks are a good idea for safety. Also makes it easier to turn your arrow the right way.
They don't fall down when dead, but walk away with the swords upside-down. It's probably safer but more confusing and doesn't give as much of a battle "feel".
Some nice battles I haven't seen before: Princess Battle with respawn points at one end of a rectangle, princess in the middle, goal is to move princess to a flag that's a bit on the opposite side of each team's respawn point. Flag battle: Similar, respawn points on same side of rectangle, flag starts in the middle, points for getting the flag to move to the opposing team's side of the rectangle.
The battlefield was essentially a saddle-point, nice for obscuring what the other team does.
Respawn was running around something, not just touching it (which prevents the "almost-touching" effect).
Conclusion: Would go again, but wouldn't convert our group to it. Our weapons are nicer, our battle is more "heroic" than "military", and I just like the garb.
-Hårdgrim
Some videos:
https://www.youtube.com/watch?v=g2KYvqQgavw (dronecam!)
https://www.youtube.com/watch?v=RkPmmDAIn5c (skirmisher helmet-cam!)