How good is Space Engineers?

I recommend you try it first somehow :P Game is still early access and basically unfinished, but they're updating it every week on thrursday.

After that you could get the game quite cheap on trading sites :}

Watch a review/Let's Play on Youtube and judge for yourself?

I found it fun only with friends, really.

PVP servers online are full of people usually extremely experienced with the game and have giant warships.

very good apparently, people bought all my copies

The name is a lie! The space was engineered before I got there...

Better try Moonbase Alpha John Madden edition, it's free and it's on Steam!