From this community alone, what is your favorite aspect of the game, "Endless Space"?

A lot of space.

The atmosphere, the resources, the graphics, the ship-building - especially ships that can hijack other ships . . .

Ship customization and hands-off battles, the latter more than the former. Don't know if anyone here played Reach for the Stars, but that was my favourite little gem way back and Endless Space scratched similar itch. ES2 just made everything around it so, so much better.

Music and space opera feel

I'd say the combination of sound/music, art, and unique races with unique gameplay features. It just makes for a pleasant experience.

The pure, unadulterated, raw , unabashed design value.
EVERY little part of Endless space is designed to be stylistic but not overwhelming.
The small parts like just colonizing a planet having a cinematic depending on the planets type alone makes me love this game beyond anything else.
The ingenious design of each faction.
(I swear, Amplitude is the only company that delves into 4X games that can make a faction of CLONES from a single madman seem REALISTIC)
The very concept of dust (born from Endless space) is ingenious and is so much better than just raw money / gold.
I just love the design from inside and out.

The ambiance of the game, how each faction feels and play different.

I love the music, art, story, race design. It really makes me want to experience every factions playthrough.

After seeing the Riftborn on a "Let's Play" on You Tube, I had to give this a try.

With GalCiv 2 being my only other space 4x experience, the races seem quite boring compared to ES2.

MOOOOOOOOODS!