I got this yesterday, and fished it in about 4-5 hours. But i have to say it was time well spent. The storyline + the small cinematic parts make you want play and learn more about what is happening on reach.
Along with the space combat, the new forge and the new game types, it gives you a large choice of what to do next after the story mode, and i can see myself spend many more hours playing this game =D.
After my first day of playing i would give this game a 8/10