One of the main reasons I decided to leave my old school, was because I was fed up to the back teeth with CMIS. We had loads of problems, and the teacher who organised the "reports" left, and I was landed with doing everything! I hated going into work each day.
When we went on some trainng courses, we had a good idea how to use CMIS, but even the "advanced" courses were full of noobs, and by the time they were up to speed, the course was over. They were too keen to get people onto training, without establishing their level of expertise, as they wanted the money. In the end the courses were a waste of time and money, as you never got past the basics. Then there we're the "updates" that required you to re-install every couple of months or so.... I could go on!
My "replacement" is off on long term sick, I guess he'd had enough of CMIS too.
That was a couple of years ago mind you, so things might have changed now, but whenever my new head says "CMIS", I just say NO
I think it's too expensive as well. So long as you're good at php and SQL, you MIGHT be able to find / use the data!