: One thing I'm not clear on this: can both players benefit from a session of
: doing this, or can only the winner collect the experience of the match?
: Because trading works, but if both can do it, I don't mind doing a
: wind-down session of this after my Wars runs each night to collect a
: little EXP while chatting with the other player about things.

: I'll admit that I've played quite a bit of Wars, yet I don't fully understand
: the EXP system. Like, I think the proper method to leave a game is to
: resign, and then quit, not outright leave. Or is it better to let the
: enemy wipe you off the map? (I try to be friendly and would rather give
: the other guy the maximum amount of exp if they've clearly beaten me)

If you quit, any points you earned don't count IIRC. Best thing to do most times if you're in a hurry is self destruct your base and send any units left to die.

The release thing is beneficial to both parties. It's weird with halo wars, but you don't necessarily need to come in first to "win". The player that places first is the player with the highest score, but that doesn't always mean they were on the winning team. I can remember a few games very early on in Halo wars where an opponent on the other team came in first while I was on the winning team and came in 3rd- they had way more kills than me and a better army. The situation was something like he played Rock while my team kept playing Paper. One of his teammates quit early on, the other soon after. We only beat him because we played more Paper than he had rocks.

On release (depending on your partner) you just keep releasing flood on your respective sides. One of you obviously will have to blow up your base to end the game, or you both could do it. Doesn't really matter. Just don't quit or the points were for nothing ;)

TL:DR

Points are points, regardless of how you get them. You don't have to "win" to get them. "Running the Show achievement" is just a points grind.