TEC and Advent starbases can phase jump??
Anyways, here's why I like Vasari starbases.
It only takes 2 military research centers to build it
They are built much faster (in the early game) than TEC (I dont know about Advent)
In the early game, you can get starbases early, and build them in a gravity well to secure that planet, because it can move around and defend it. They can also move to assist your fledgeling fleet which is good and prevent colony ships or bombarding shift from accessing the planet before you can afford to fortify it. You only need upgrade the starbase.
When assaulting a well fortified TEC or Advent gravity well, they can be built safely away from their starbase, then move and assist in the battle against their starbase.
It can be upgraded to have the highest hull, armour, attack; and its shield and shield mitigation are much higher than TEC.
When your playing against 3 hard and 2 unfair AI's in a medium-large galaxy and prefer not making allies and dominating yourself, every planet/asteroid you secure early is the difference between life and death.
Anyways, I am playing TEC now and I have the big red button.. It's on "autocast" but it never seems to actually autocast. I had 5 enemy hard AI's assault my maximum fortified planet at the same time with my entire fleet defending, I got wiped out and the big red button doesnt go off. Needless to say I lost that game 