Bylamp
Wow. Although it seems the assembly line type seems very productive everyone would have to be very cooperative. Deadlines ... I don't know what to say about them. It's a love-hate relationship. Haha.
Sometimes the "collaborators" don't even intersect, so it's not about being cooperative, it's about meeting deadlines. It's up to the project coordinator (editor) to make sure these deadlines are well-designed.
As an artist gains notoriety, they can exert more influence over this system, such as the penciller being able to pick the inker they'd like to work with.
With good management, it can be very productive, but it requires a professional approach and a respect for deadlines. In amateur projects, deadlines are often flexible and self-imposed (not to mention the artists probably have school or day jobs), so it's harder to keep the team on task. I have seen it work in an amateur project though, so I have some faith in it.
Personally, I prefer the one-man-band approach, but that's because I'm in no rush to get my comics out the door.