Each expansion to the beta makes it better and better. Just started my first game as Yor with the Krynn Consultate as a opposing race, and I have to tell you it's nice to not be picked on right by everybody from the start for once.

The new tech trees are great, and a lot of fun to explore. But they still need a lot of tweaking to get the bugs out. My poor Yor still have a hard time keeping Mining Bases close to enemy territory without building hordes of Influence Bases around them.
Terror Stars are great one shot, one kill weapons against factions that are down to single systems. At least for now, if you go to war with a race while attacking it with a TS, and wipe it out in one shot, that race's allies won't declare war on you. Makes sense in a way, why go to war over someone who got destroyed before they could declare war themselves?
That said, TS make great area denial weapons. I like to use them on five-planet systems where the enemy has maybe one, poor quality planet, then come in with five miners to start harvesting the resulting asteroids. Even if there are no habitable planets in a system, I still use the TS on it for the usable asteroids. Heh heh, I'll even go so far as to blow up solitary stars just to clear up the map. The only problem is when the AI decides to stick Influence Bases all over the damn map in dead systems and I don't want to go to war with them.