two quick questions:

1) Do you recommend using the official G2G Balance Mod? What are the pros and cons of using it?

2) I'd like to try 'endless' speed (I like slow games). Is it balanced? Does it work fine with the G2G Balance Mod?

Thanks in advance

I would definitely recommend trying the G2G Balance Mod: it contains the most up-to-date changes in game balance that, if they receive positive feedback, will then be implemented in the game. The only con I can see is not being able to unlock achievements while you use it.

I generally wouldn't recommend Endless Speed, but that's because I usually like playing in Fast. The balance will be slightly different with each game speed, because of the respective empires' time needed to come online and perform at their best.

I recommend Endless speed. I love the slow build of the game.  Otherwise, it feels like the beginning lasts forever, the mid game is zoomed through and the end game comes too fast.  But heck! This is why there are different options.

The one bad thing, is that as the game gets going and you have so much going on, it becomes very difficult to put the game down for a few days and then come back to it and remember what you were attempting to do with each and every fleet, planet and action.  =)