Star Ruler and Sword of the Stars (SotS) share a lot of problems. I liked both games in theory, but prolongued, repeated play was stiffled by the simplicity of the management parts.
For example, Star Ruler does have a nice colony buildup ala Civilisation (list of buildings per planet) with space constrains based on the size of planets. But there never really is a reason to micromanage them besides the first two planets or so. Just set the governor AI to one of the handful default builds, and you'll be done with colony management.
While you can create ship models (no visual changes), there is no reason to specialise them as general designs work much better for the combat model of this game. Of course, building more or less the same ship in different sizes over and over is not very interesting. In the end I favoured heavy armor/shield builds with one or two weapons, and a few repair modules. Survivability is cost effective, and going all out in weapon use is not possible due to the crew/ai and power constrain model used.
Diplomacy is nonexistent, as you can't become friends with the AI at all, and the main focus of the game is to expand as quickly as possible, without outproducing your resource income, at which point your empire would be crippled, and overcome by the competitions size advantage. The diplomatic AI in general seems to revolve around a simple true/false question wether they're bigger or smaller then you (with war when they're bigger and random, often unfullfillabe trade deals otherwise).
I was too bored with the overall mechanic to really solve the overextension growth puzzle. I guess I was probably supposed to only colonise fabulous planets in the beginning, taking the less interesting ones later on. Combat is determined by whom has the bigger production, respectively who has more ships at the battle system. That is also why jump drives are vastly overpowered, and the most important technology to get.
Technology research in general is weird and seems to only exist to postpone the key techs like bigger ships. Colonies get minor updates to their buildings from Techs, but they are applied automatically and should always be done. Technology has an automation checkmark, and I suggest leaving it on, because all advancement stops once the queue runs out, and I often forget to set it. In addition, what you research first is pretty inconsequential. Despite the automation, you do need to choose manually which closed tech paths to open, it can take up to 5 tries. But again, you'll want them all, and the only decision is when to get which, so no risk/reward or other choice needed. The tech tree is not randomised at all.
I did win against an easy ai twice, and started about 6 games, before putting the game aside. I will most likely not play it again. Because of that, I'd say the price is slightly too high for the entertainment that it gives. Oh, and also: Whole game is real time, not turn based, which leads to me pausing the game all the time, making gameplay feel slow and weirdly boring (nothing important ever happens syndrome, similar to eu3 and other paradox offerings).