I'll keep it short.
I have 2 friends I've played multiplayer with. Friend #1 can connect with me, regardless which of us host, but it takes 3-5 mins to load the actual game. The local player loads in but it takes forever for the other person to finally load. It works fairly well once loaded other than some obvious lag/desync here and there.
Friend #2 when hosting loads very quickly, not long after he loads locally I can load into his game. When we all 3 play, as long as friend #2 hosts then friend #1 and myself can connect normally.
Here's the weird part. Me and friend #1 have the fastest internet and fastest computers but have the most trouble. Friend #2 has a much weaker computer and slower internet yet works out as the best host.
We've tried firewall settings, hamachi and everything possible and nothing helps. Any clues?