I got some real time in with it yesterday and allow me to state that LLF is giving excellent advice above, in all particulars. When you go to the roof tops all #$%^& T%^&*** breaks loose and you cant possibly suppress all the bad guys in time.
The thing about staying in the street really works as well. You have to kind of retrain yourself from playing heavier forces on more open maps, where streets are suicide. It is really kind of a large mental shift. While the marines are under armed compared to most CMSF scenarios, so are the bad guys. It just requires a very different approach.
The map is amazing, and the whole thing is nail biting fun.