A lot of people still is playing SE3 (and think that will continue playing after SE4, during a long time).
Go to the Borg: http://www.vendetta.net/borg/index.html
Yes, the se4 demo is really good but, I stoped playing it as well at 100 turns things are really just starting - I find in the game. So I will just have to wait for my full Version to arrive in the mail box...