@IXNAT
Is continuing education a waste of time ? I don't think so in any industry that is driven by procedure, licencing and knowledge.
How can a qualification be "essential for many positions" yet "a waste of time". I don't follow your train of thought at all.
In terms of accreditation there are institutions like RAeS, there are government organisations that rate universities based on staff and research output, there are employers that sponsor students that have a view, and of course there are students that have actually done it , maybe with their own money.
Ask any of the above what they think about a particular course.
hugel