I decided to put the races through the ringer to see how well they stacked up with each other.
I used a large map, spiral, 4 total players , old galaxy. I left random events on because I wanted to see if I got the same random events consistently which I did. I wanted limited outside influence from the Ai races to keep the test controlled. The Seed I used was 19.

My end point in the scenario was researching Galactic Networking (I call it Galactic Quantitative Easing) and building a Doom Star with Adamantine armor and a full compliment of Zeon missiles.

Sakkra 212 turns
Psilon 220 (I could probably do better next time as I refined my strategy after this game)
Bulrathi 236
Mrrshan 250
Humans 245 (but I cheated my rules a little and formed two rounds of trade treaties because their cash production was pathetic)
Alkari 270

My only surprise is that the humans were even close to the Mrrshan and Bulrathi.

My conclusion is all other things being equal the Sakkra and the Psilon will crush the other races every time.

Mrrshan's infantry bonus is limited because of the amount of time and resources that need to be spent to produce troop transports.

Humans' trade deal bonus only works with the Ai and with the current state of the Ai even with the proper tech advances
it's tough to maintain a prolonged trade treaty with more than one race. Once spies are in game humans can be re-evaluated, but with the near creative level of tech advances currently in game spying will be of limited use.

Alkari's defense against beam weapons is nearly worthless now with how over-effective missiles are.

I noticed the Sakkra are quite powerful with the reduced food requirements, especially after some boosts to food production. With fewer colonists working food, more can be placed into production and/or science.

Wow. The Alkari are much worse than I though they'd be.

I agree with all of this.

With the new custom races it's clear that growth, food and monetary bonuses are the top three most powerful attributes.