I run construction projects for my company, but rely on a lot of outside players (arch, CivE, Struct, MEP, GC). Huge part of my job is just managing the individual strands, and finding out when one of those subs talks to each other but doesn't update me/my company. I've had almost no luck having these groups sign up for something like a light collaborate work tool.

Instead it's all e-mail and face-to-faces (at their high billing rates). Slows me down so much compared to my internal projects where we can have a Slack chatroom or google-docs/evernote organization system to keep track of everything.