These were interesting tools. I found Google's version much easier to use; however, Zoho seemed to have lots more bells and whistles. For basic text editing by a group that had a variety comfort levels with the software, Google would be by far the better choice. However, for anything involving graphic design, Zoho might be more useful.
I can't see that these tools would be very useful for working directly with the public. I can see that they would be a fantastic resource for regional committees trying to put together any sort of project (RFP specifications, new policies, brochures, etc) since they would allow each member to contribute wording and comments at their own pace.