Sins is ok (talking about Trinity), but it's no Homeworld. The space battles are more like Risk battles with a wee bit of tactics involved. It's a standard RTS version of a standard 4X game---no more, no less.
The most unique features are the pirate raid bidding and the vaguely DOTA-like Capital ships.
I picked it up for $10 this year on sale, and I'd say that is its worth. Gal Civ2 Ultimate was more fun overall for me, as a Civ4 fan.