Over the years, I've wanted to run a sci fi campaign, and I have collected A LOT of different games in hopes of getting one to launch with my group. Alien RPG, Stars Without Numbers, Eclipse Phase, 40k games, Star Wars FFG, Traveller, etc. An eclectic mix to say the least. The reason I love M-space, is because it's a versatile toolkit that helps me tell any store in any tone that I like.
The rules mechanisms are beautiful and easy to learn (Disclosure: I dig d%, skills-based games). The Special Effects aspect of combat seems a bit tricky from a learning curve perspective, but also adds some flair to combat. Starship/vehicle design, alien and world design, this game has exactly what I need at the perfect level of abstraction:detail that I need.
What I love most about this game, is that I can take any published adventure in any of the different systems I noted above and easily convert those adventures into M-space. This means my sci fi exploration campaign can land my team of players anywhere and I can radicaly change tone to reflect a new world or the party's mood.
[5 of 5 Stars!]