I used a set up to play the game with minimal interruption from the Ai to best test to balance of each race.
The score of each race is two part based on the time it takes to research Galactic Networking and the second score the turn in which a Doom Star is built with adamantine armor and other bells and whistles (if built with max missiles then it will be a strength of around 550K) The lower the score the better.

Meklar 162/188
Sakkra 157/194
Psilon 161/200
Klackon 173/207
Bulrathi 175/208
Alkari 182/215
Human 184/228 Alkari, Human and Mrrshan difference is probably based on a slight change of play style.
Terran 180/231 Terran should probably be better. I will do another game with them in the future.
Mrrshan (I did not use them. They should have a score about the same as the Alkari/Human)

These scores do not reflect a direct ability of each race to dominate a game. Certainly Mrrshan, Alkari, Meklar and to a lesser extent Terran would benefit from their ship abilities. This would make the Meklar stronger still.

These scores all fall short compared to the better made custom races the best of which I have made so far has a score of 134/149.

I posted a chart on how I think the customize race attributes should be. I think those would help even things out. I think that the standard races should be beefed up some with some getting more beef than others. I understand that spying is not in game yet, but trust me that when a technologically more advanced opponent is producing about 5K credits a turn around turn 160 no amount of spying is going to stop them.