Pros:

Interesting Location
Well made
Gorgeous view of space
Great design
Fits into Left 4 Dead AND Half Life universes
GLaDOS commentary
Good weapon placements
A story is made without telling you (infection spread to the space station with attempted surgery on a Boomer, a Tank being held and a "Quarantine Room")

Cons:

Pretty unrealistic (Why would there be an armory on a space station?!)
Tanks sometimes got stuck in small hallways
GLaDOS doesn't say much

Conclusion:

An extremely well made map, I was amazed the story telling done in this map without a single word beign said by a human. The view of Earth from the main control room is spectacular and breathtaking. I think that while this map isn't perfect, it's on it's way to being there. Would like there to be a trigger like maybe you attempt to mess with the controls (a button or switch being the trigger) and GLaDOS detects you trying to mess with it which would activate the mode.