I've seen companies waste some pretty serious time on admin and maintenance of room reservation screens by the doors. Oddly enough they had chose not to go with an iPad based system because of cost
I assume there was some maintenance cost, but the biggest problem I saw with the tablets was there was nothing preventing anyone from deleting somebody else's meeting and replacing it with their own. There was authentication on the web interface, but nothing if you just directly edited the schedule on the tablet.
At least with the paper-on-clipboard, it's obvious if an existing meeting was crossed out.
The enterprise systems tie in to your Exchange / Outlook messaging for shared calendars. We saw excessive equipment failures with the Steelcase line. This was a few years ago. But like I said, they had the option of using iPads, but went with the proprietary solution instead -- which was NOT reliable for deployment.