Best Sci-fi TTRPG?

I'm putting together a universe for a horror sci-fi setting and I've never played any games in the genre outside of SW5E.  Anyone have any suggestions? If so, please say why. In addition to something that supports homebrew well I am also hoping to find something integrated into Roll20 nicely. Please let me know your thoughts in detail.

My favorites are: Last Parsec (by Pinnacle Entertainment) - Why? Because it's Savage Worlds, which is my go-to gaming system. Savage Worlds Core rules are on Roll20 as a compendium as well as several add-ons, etc. The Last Parsec setting, specifically, isn't on R20, yet, but I'm hopeful it gets here at some point. However, because it uses the core rules for the most part, there would be some manual and some drag and drop support. Coriolis (by Free League) - Why? Because Arabian Nights in Space is just awesome. The Mutant Year Zero engine is a ton of fun and the game evokes a lot of ideas for me. There's a character sheet, but no compendium currently. I hope they get support on R20 soon, because if they do, I'll change from FVTT for Coriolis to R20 in a heartbeat.

Alien RPG (by Free League) - Similar to Coriolis, as it also uses a modified Mutant Year Zero engine. If you really want to play up the horror aspect of your sci-fi setting, Alien RPG has a great stress mechanic that really amplifies tension and generates a lot of that sci-fi horror feel through actual game mechanics. Can be pretty easily mashed together with Coriolis if you want to file off all the Alien franchise specific stuff. Doesn't have Compendium support yet, but there are modules on the marketplace and a solid character sheet.

Loren the GM said: Alien RPG (by Free League) - Similar to Coriolis, as it also uses a modified Mutant Year Zero engine. If you really want to play up the horror aspect of your sci-fi setting, Alien RPG has a great stress mechanic that really amplifies tension and generates a lot of that sci-fi horror feel through actual game mechanics. Can be pretty easily mashed together with Coriolis if you want to file off all the Alien franchise specific stuff. Doesn't have Compendium support yet, but there are modules on the marketplace and a solid character sheet. That's one I've wanted to play, but haven't had the opportunity, yet...everyone I've heard talk about it really speaks positively about it.  Just need to dig into it myself, now. :)

M-Space - I'm biased as I've written for them, but the Extended Conflict rules transform the entire roleplaying experience IMO. It's also got the advantage that it's made setting free with the idea that you can use the system for any scifi setting, from the Expanse to Star Wars.