Alliance are a serie of different mods. On the Star Wars GC, you can play the civil war Empire vs Rebel era + Black Sun and soon the Republic and CIS.
Well, I have been working a lot in this last proyect. The idea is to create some the most similar to the old SW Rebellion game. Lately my last addition was the heroes recruitment, now you get some normal heroes as the original game in the different tech levels but you must recruit heroes with a mission in a way similar to the SW Rebellion. You must buy the recruit mission.
These new recruited heroes are minor heroes and they can die in battle, in fact, even you can lose the mayour heroes. However the minor heroes can be recruited again and it is good because you will need them researching new technology and building new units.
The recruited heroes from missions are get randomly. With the Empire, Vader and the Emperor can recruit the same heroes. But Tarkin can recruit heroes and in addition, it can recruit two more heroes than the Emperor and Vader. Other heroes can make similar things. Of course, when I publish the mod, I will public a complete guide about this.
About GC itself, yes, there is lag but it is a 167 planets GC, I am sure how you can not run some like that faster, even with the original game.;) It is the price by one big GC.