If we are going to brag, I'm on a 250/250 connection.

But this topic appears to be related to: https://forums.factorio.com/viewtopic.php?f=7&t=26045

Also it would be trivial to either use a server in a ddos by spoofing your IP address or disabling the server by using up all the upload speed.
So ...

28kb/s upload? What is this, 2004??

Australia.... -_- and mine is the fastest out of our whole group =/

Either way, why is it uploading so much? Every other game I've ever played has never used this much upload data.

It's almost as if the game is flooding (or DDoSing) my modem and then getting ...

I am having the same issue, I can sometimes host from my PC, sometimes it sits at 3-4kb/sec and its all smooth. However most of the time it's uploading at my max speed of 28kb/sec and it just lags like crazy. Also when a friend is connecting and downloading the map, he downloads it at 5kb/sec ...