Sins of a Solar Empire is to GC2 what Age of Empires is to Civilization. Can't really compare that.
A better comparison imo would be comparing GalCivII to Space Empires IV or V, although the interface in SE svcks raw eggs..
GalCivII is fun as hell, and it's major selling point is modability (already mentioned by TTP -gotta check out the Bab5 mod :goodjob: ) and the ship design interface -all my ship design resemble 18th century sailing ships :biggrin:
MOO3 is available through GoG.com for $9.99, and pretty good once you patch it and get the balancing mod for it (can't remember the name for it) atm I'm playing MOO2 and having a blast :disco:
My only beef with the genre is that out of all 4x games, the ground combat and planetary invasion invariably blow chunks. :pinch:
I guess my choice is then GalCivII or the MOO series..