Hmm... I've played all of those.
Distant Worlds is bloody amazing, though it feels dated obviously. I think it's still better than Stellaris though. That being said, it also has the issue where you kinda run out of shit to do in the late game. Feels less gamey than Stellaris though, if you catch my meaning. Feels more like a living breathing galaxy and you feel more like a galactic Emperor rather than a galactic micromanager.
I still maintain Polaris Sector is fantastic for small scale gameplay. The combat and customization is fun and the lore text is frigging funny. It's one of those games that describes humans like how aliens would describe humans. That being said, it's fairly limited in scope. Also a lot of people don't like it.
Pandora First Contact sounds like it's amazing. It sounds like a sequel to Alpha Centauri. I can tell you it's basically the same as Beyond Earth. Soulless, boring, no fun. That being said, I only played the release version so no clue if it's good now. It's only $8 so... maybe try it? It's not worse than Beyond Earth I can tell you that. It'll probably be alright if you go in not expecting it to be Alpha Centauri.
Star Hammer is alright. Pretty fun campaign too. It's got a Homeworld-esque combat system though but it's not particularly deep or engaging in my opinion. It's basically a crappier version of Nexus: Jupiter Incident, which I adore.
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Edit:
Incidentally,
World in Conflict is free right now on Uplay.World in Conflict's campaign is superb. Easily one of the best RTS campaigns ever made. I highly recommend it.
This game broke my Tunguska virginity. Before this game I was unaware of the awesome girth of the Tunguska. Post-WiC, I now bow to the superiority of the mighty barrels and penetrating missiles of the air sweeper. Also I really should impress how good the campaign is. It's not like a traditional RTS with base building, more of a squad command thing... combined with Wargame's combined arms warfare. Again, I highly, highly recommend it. Despite Uplay.
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Edit edit:
Also this is reply
#15000!I hereby declare this a party!!!!