SotS is the best space 4X I've ever played. I love it so.
SotS is the second best one in my opinion... MoO2 being the best.
I love that you can build races that play very differently in MoO2.
SotS races DO play differently but everything is pre set whether I like it or not. However SotS has the best combat system to date of any 4x game especially if you include the mods. Well SotS 1 does SotS 2 was a royal mess that destroyed the company it was so bad.