I mean ... it's so convenient to walk across the room and speak with a structural engineer about an issue that impacts building design. It's gratifying to communicate in real time with an interior designer and work out an architectural issue that affects something indoors. It's easy to wander downstairs and ask a plumbing or mechanical engineer to quickly explain a system for my understanding. Rather than shoot off an email, transfer a file over FTP or wait for outside consultants to get back to me, I can move forward immediately. I have face-to-face resources, accessible and available to collaborate in the same office, everyday!
I can learn from them, and they from me. Together, we can resolve issues and hurdle problems early on, before it's too late or inconvenient to address. And even when a change inconveniences my work, I appreciate the notice, because we still have a chance to work toward a mutually beneficial resolution, rather than let the issue fester. All in all, it's a pretty swell deal.
Now, maybe this sounds like the ravings of an over-euphoric zealot, but having worked in this system for nearly two years (and this being my first full-time experience since graduation), I can't imagine using the traditional means of coordination with various engineers and consultants on a point-to-point basis. Well ... I can, but I wouldn't want to. Sure, some might say that an integrated office means that designers and engineers are exposed to each other too often, but the benefits outweigh the occasional instance when we drive each other crazy.
As a culture, integrated sustainable design returns us closer to the historical role of the Master Builder. When all cogs come from one source, the machine just functions better, and that invariably results in a better product. It's a process that, I must say, has positively spoiled me.
LINKS
http://en.wikipedia.org/wiki/Sustainable_design
http://www.gsa.gov/portal/content/104462
http://www.sustainabledesign.com/
http://www.nps.gov/dsc/d_publications/d_1_gpsd.htm