Being very expierenced GM that I am, I hate being dictated by the rules on how should I run my games, which is the reason I don't really buy into modern RPG design. BRP family is one of a kind; a tabletop-rules systems that is what RPGs were supposed to be in my eyes - a toolbox of rules and statistics that paves the way to our imaginations and helps bringing balance to the adventures and worlds that we create. No more, no less. This is what M-SPACE truely is. It is a complete system, one that does not require you to add or substract anything from in order to run your space-faring game. However it will also not break if you decide to do things your own way, which is not a common thing in a modern era of RPGs, that resemble board games with rules that are there to limit your potential and your imagination, so that every game session plays at the same, rather average level. There are no rules that will dictate how your players should roleplay their characters or how you should run your games. It's a sandbox of a rules system, which means that it has all the necessary rules to run a game in a SCI-FI universe - from PC's skills and attributes to equipment, combat rules, space-faring, alien creation, force (psionic) users and world building.
You can run anything SCI-FI related with M-SPACE and with very little changes. You can easily create Jedi Knight with the rules written here, Space Marine, galactic politican or Stormtrooper. As it is with all the BRP-related games; M-SPACE is very universal in a sense that every character, monster or robot is made of characteristics, attributes and skills. They all follow the same rules, making them more believable and easy to create. I could write much more on why D100 is the best system ever, but it has been said already so many times on the internet, that I don't see a point of repeating what other great minds have already said ;)
I cannot recommend more this game. Buy it! It's the best SCI-FI system that I know, that's for sure.
[5 of 5 Stars!]