Machine Empires have 100% habitability everywhere so they should go wide and colonize everything. Population growth is key and they need help in that department, so the more planets they control the better.
Machine Empires can make good use of habitats for research or energy production.
Remember, Population growth rate is the following for Machine Empires: (with 10%/20%/30% bonus)
Colony outpost only: 100 months per pop. (91/84/76)
Colony outpost plus Robot assembly (5 pops): 50 months per pop.(46/42/39)
Administration (10 pops): 34 months per pop. (rounding issues) (31/28/26)
Planetary Administration (40 pops): 25 months per pop. (23/21/20)
Highest level administration (80 pops): 20 months per pop. (19/17/16)
For my play I was using the 20% faster build speed robots, and I quickly got the +10% build speed tech. With 5 planets, 4 at Administration and 1 at Planetary, It takes me no more than 52 months to build up another planet to 10 pops. That planet will also produce exactly 1 pop on it's own before it's done. At 2075 where I'm at, I have 12 colonies producing 123 populations every 130 months.
Early game, you pretty much have to become a factory for building robots in order to make it. As I said, any sort of war can really set you behind by decades. It's not optimal, but the possibility exists.
Edit: I must have done my math wrong on how quickly you make populations, in my game I'm clearly exceeding that population growth. As I said, I'm at 359 populations at year 2275.
Edit 2: I found my error, it's every 130 months, or about 11 years, not 130 years. I blame that on fatigue from work.
