I admittedly am still learning them. but they are pretty powerful.  get scavenge up high & camp out by enemy planets, send their own transports against them.  Play them more like the yor 

As Tetrasodium said, scavenge their transports.  They come with troops and all.  Use info warfare to keep the starting pop high and quickly build farms before they die off.  

The scavenge ability can keep your economy from going bust.  You just need to use it a lot.  Small and tiny ships give some bcs, but later, you'll be getting medium and large ships.  I have to admit that once you're scavenging every attack, it gets old.  

Don't build the solar power plant.  It's pretty useless.  There's another structure I build in its place, but I can't remember what it is.  I haven't gotten back to GalCiv3 in a while.

They're very slow to reproduce.  In my current game, most of my planets can handle over 100 pop each and some go up to the 160s.  The pop isn't anywhere near that and might not get there before the end of the game. 

I only have 2 planets with labs and both of those only have a few.  They came with high research bonuses.  If they have +50% bonus or less, I ignore it and build it out as if it were any other planet.  I've traded for most of my techs, so labs are kind of redundant for me.

Everyone loves me in my most recent game.  It just comes down to power.  Even the Altarians are close.

Yes, you get credits, and yes, it's when you decommission them. It's not that much money, usually, however.

I wouldn't bother getting population caps anywhere near this without modding the game, certainly not now that Birthing Subsidies is capped to +100% growth; the base population growth rate is only 0.1 per turn, and even with all the bonuses you can toss on it you're only looking at a growth rate of perhaps 0.5 per turn at best. You'd need ~200-1000 turns to fill the planet; such large population caps simply aren't worthwhile. Bit difficult to justify going over perhaps 30 food per planet, really; you're looking at ~60-300 turns to fill the planet. It just takes way too long for populations to grow to the point that all those food structures are useful. Only factions with access to one or more of the assembly projects can reasonably bother with such high population caps; they're the only ones who can get the populations up quickly enough for that not to be just so much wasted space for the entire game.

You get a base synthetic population cap of 15 on every world and you get the basic Assembly project when you pick the Synthetic faction trait. A synthetic faction that isn't using the Yor tree is therefore workable, though the inability to increase the population cap is somewhat problematic and having access to only the basic Assembly project isn't great (and yet still greatly superior to natural population growth on any planet that can put out more than 101 manufacturing per turn, as that translates to a population growth rate of 2 per turn).

NO NO NO do not decommission sell them in a trade to the AI

DOH,  Musta had a brain fart, can't believe i never thought of that

Probably because birthing subsidies, growth enhancing improvements, growth enhancing planetary doodads & various traded growth enhancing techs stacking together give the even the thalan ridiculously better growth than you can get from assembly & yor.  By not including it, they can gather data on how tweaking it can/should be done without hitting all the other races like the yor got hit in 1.3

On smaller sized maps, couldn't one start as Snathi, rush weapon tech's first thing, and then proceed to put a gun and tons of engines on starting ships and intercept the early colony spam? This way, you'd end up with a solid military, and a massive number of planets right from the get go.

It'd be even more terrifying on a custom Snathi race. Intuitive so that you can have a gun and better engines on turn 1. Refit your starting scout, rush buy the ships as fast as you can, and continue to do the same. You could have the Adventurous/Fast traits maxed to minimize the need for life support, and could easily throw a constructor or two in to the mix to build starbases for the sake of extending fleet range.

Hell, even if you don't restrict yourself to smaller sized maps, I'm sure this could be made to work regardless as long as you avoid the enemy sensor ship until you can combat it with a combination of yours and some high-speed escorts.

I might have to buy the DLC now...

EDIT: Wouldn't having lots of pirates benefit them as well? Don't have to build as many crappy ships if you can just take them from Captain Jack. He never could hold on to his ship very long any way.

yes significantly since you can put off researching weapons techs while researching other stuff while your fleet of pirate ships bluffs your military power up

Can you retrofit those ships with some basic thrusters?

You can only have one of these per planet, and in my post I counted the Replication Center (+150% base, +5% per level, assumed level 10 => +200% growth).

You can only have one of these per planet, and it's +10% growth per level, not a flat +10% growth; I assumed level 10, so +100% growth.

You only get one of these, and the second is actually a growth penalty; why you brought it up in a discussion of whose growth is faster I have no idea, as it penalizes natural growth and does nothing to artificial growth.

1. Good luck getting it.

2. Whoop dee doo, I get a whole extra 0.01 population per turn. +10% population growth is not worth taking; the +10% research is better for a research or mixed world, and the +10% influence at least has a real effect.

Adds up to exactly the same +60% growth from techs that I came up with from the Terran tech tree.

None of them compound with one another, as not one single one of these bonuses can multiply any of the others. It's straight additive stacking, and you end up with something around +500% population growth at best, which works out to 0.6 population per turn. This is laughably small by comparison to the attainable population growth rates using even the basic Assembly project; I need merely ~33 manufacturing output to match this.

I will further point out that assuming a level 10 Food Distribution Center (or upgrade thereof) and a level 10 Replication Center incorporates the tile bonuses you've listed. I can get at most 6 adjacent tiles (6 levels if filled with farms, 7 levels if the FDC and RC are adjacent and the other tiles are filled with farms, 8 levels if one of the tiles that is adjacent to both the FDC and RC is filled with Artocarpus Viriles or a Monsatium Deposit and the FDC and RC are adjacent to one another). Given that this requires that I build ~10 farms and have at least a Food Distribution Center on the planet, I'm looking at a minimum of about +50 food on the planet (4 food per farm, 2 from the base value and 2 from being level 4, +25% from having a Food Distribution Center) unless I'm on a planet with a food penalty. At 0.6 population growth per turn, it is going to take ~83 turns for the population to use this food. This is not likely to be worthwhile.

the list was mosytly made because I noted it a while back when I was working on ILO (as noted in the post).  while it's true that it would take a long time for a population to use massive food bonuses the thing that makes synthetic pop tough after 1.3 is not being able to stick a colony to 100% industry while building some ,fg yor/assembly meaning the time it takes to build it is quite a bit longer than the ~15-20 turns nonsynthetic races would need for that first 2mil bump in pop