Hmm ... which factions do best last game?

• Iconian due to repair and no maintenance
• Yor due to massive construction?
• I guess if you stacked a lot of hives, maybe Thalan would do very well late game a well?

Terran: Nothing.

Drengin: The Slave hubs are basicly the best (colony-unique) thing you can place on a tile in the game. Adjacencies properties are insane. The Approval bonus from the manufacturing buildings is nice, too. They also have stronger approval buildings, which compensate for the higher foodcap through their slave- and food-hubs (gets +% food adjacency instead of +% growth).

Altarian: The social matrix is a nice combined research/manufacturing hub. Their approval buildings are slightly better I think. The downside is they ahve a terraforming improvement less. The have a 10% jamming tech.

Iridium: combined influence/wealth buildings.

Krynn: combined approval/influence buildings primarily.

Yor: Tech tree for the synthetics trait, which focusses on building instead of breeding population. Lacks manufacturing and research capitals, which hurts.

Iconian: Strong Ship improvement techs. Unique hub gives a slight boost to food. They also have a special research building.

Thalan: Hive tech is amazing. Especially after base colony production nerf. Hyperion matrix is an amazing research unique and directly and conveniently leads to deeper knowledge. Also has useful fleet boosters like jamming and additional hull capacity boosts.

Torian: Strong Ship improvement techs (20% jamming and 20% damage reduction). Have slightly better food buildings and approval buildings with better adjacency (gives to everything). A downside is there different tech building tree, which lacks hubs and the research capital. Life support takes more space, but provides higher reach.

Arcean: Can build manufacturing and research galaxy uniques in the age of war, long before any other faction. Movement boosters and a semi-unique ship repair tree.

Snathi: Hub buildings from Iconians, Drengin and Altarian (very strong), techs boost the chances of conquering enemy ships after battle, super-cute leader 3d model. BUT: Can't upgrade growth improvements and totally lacks counters to jamming.

There is some more minor stuff about techs being accesible in the first age, but the above are the most important points I think.

How without adjancies from a powerplant being a population improvement, not manufacturing, or research improvement. I counted them they still have the same amount of power plant buildings, but suffer from one sided adjancies. Also only having one population improvement limits the possibility of creating a late game planet that's a high population all production given I have not seen a all production planet superior. Having only one population improvement gives them the lowest cap on any race on a planet class eight or higher. By the time you could max out all your population everyone else will have more population anyways due to multiple improvements. Also better research, or manufacturing due to better power plants better bonuses giving two way adjancies. Also capitals. With more population on bigger planets. 

Also this late game with maxed out population is only good for small maps that have a war strategy. On a insane map with forty races, even on a war strategy you wouldn't beat enough factions before everyone has more population due to multiple farms. You know in two there was a approval penalty when you went above 20 if it was still there then this would be advantageous for the Your.

Yes I meant Yor. Sorry

Thalans have the best early economy due to Hives. Later in the game manufacturing is best maximized via population + starbases. The Drengin are very good due to high popcap.

Choosing the malevolent tree has a huge impact on late game production, too.

With a custom Drengin tech tree factions I managed to have multiple 150+ population worlds before turn 200 (before 1.9). You may want to use birthing subsidies for this though, once you have high manufacturing on a world and if you don't want/need to build a fleet.

The more significant factor is however, your early game. The game is often decided before everyone can max their tech and worlds and the earlier you reach the lategame, the better. (Hint: Thalan).

I usually play on large or huge galaxies on genius, so the above may not be practical in larger ones or higher difficulties.