So just recently started playing with synthetics, and I think it's OP by the midgame. There are lots of tradeoffs, but in the end, Synthetics come out on top:
Advantage: More planet tiles due to farm/hospital elimination
Counterbalance: Buildings are weaker (Mfg Yor = +10% versus Terran Factory = +25%); wealth buildings capped to tier 1
Advantage: 4 free race editor points (no need for farming or reproduction)
Counterbalance: Costs one trait (Synthetic when you could have been Intuitive, Prolific, or Patriotic)
All of the above cancel each other out pretty well, then we get to the kicker:
Advantage: Can manufacture 2/4/6/8 million population at a time
(Insufficient) Counterbalance: Opportunity cost of that production time + unintuitive build sequences
The production time cost becomes insignificant by the midgame, and the build sequences can be mathed out once and disseminated to all (Reach 5+ pop before building your first 4 factories). In the meantime, the advantage of the insane population growth won't even diminish in 1.02 (if I'm reading the patch notes correctly).
The counterbalance for this just isn't enough.
What does everyone else think?