AfterShafter
Deity
BTS is easier, in my opinion, once you've learned to manipulate the new systems added to the game to your advantage. Espionage, colonies, and corporations are three more things that the CPU will use poorly which you can use well. Prior to getting a very firm handle on these systems though, it was tougher. I dropped down a difficulty to start BTS, and found it tough, but now that I'm fairly handy with espionage, mainly, I'm up a difficulty from where I was in Warlords.