I never really gave SOTS much of a go as it seemed too much of a 'click fest' for me at the time. Sins I liked quite a lot because you could anticipate the attack waves and setup tower defense in key systems - which meant you could focus on one battle while allowing the defense to handle the waves.
I tend to like turn based games or RTS games that play like turn based. Getting old I guess.
Actually, AI War is very similar to Sins in many ways. The only real difference is that in Sins you can reach a critical mass and then steam-roll through the AI quite easily because they are building forces the same way you are. This doesn't tend to happen in AI War because the threat counter and spawning ships keeps a parity.