We used to always set up colonies and platium. But the games tend to be about the platinum.
Now we stopped setting up platinum, but kept the colonies. And i must say, it plays great. It takes an bit longer, but it is really about an building an good deck. And not in the way it is woth provinces, where the game evolves in the end game rather quickly.
So how do other people decide wether colonies/platinum is added to the game?