Degree

Whether MEM or MIM depends on your aptitude:
If you can relate to manufacturing industry and are good at (your undergraduate specialisation of ) engineering, MEM is the way to go.
MIM deals with Information Management, and needs further specialisation in a certain type of operations or sub-operation (e. g. manufacturing, logistics, sales, A. S. etc. )
Most practitioners of Information Management in the industry for the last 25 years or more didn't need MIM, which is a fairly recent introduction in educational institutions. Whether it will be needed in the future is also not known - employers don't ask for it or prefer it, they prefer practical knowledge over theory, especially when information systems almost everywhere are driven by packaged software (which MIM doesn't deal with for obvious reasons).
MEM has more scope for innovation than MIM. MEM also is not mandatory in industry, nor is it an insurance against unemployment. If at all, industry prefers to recruit people with PhDs in a relevant specialisation (more direct benefits than MEM or MIM)
Knowing that academia needs people with Masters degree at least (one needs a Ph.D. to become a Professor), MEM / MIM etc. Seem to be more geared up towards academics
RoI and career growth: This is COMPLETELY dependent on your ability to solve problems and bring innovation to your place of work. Other than a Ph.D. in specific topics, which sharpens the ability to solve problems and bring innovation, no educational degree or certificate gives a guarantee of career growth! For that, it is your skills and ability to apply knowledge that matters. It is possible to grow in life (not career) by being mediocre and not being special - almost everyone grows in their lives. The ones who think they are being smart by preselecting high career growth paths also grow at the same rate. It is only those who are able to proactively apply their minds and practically use their skills, are the ones who grow at a faster rate. Most of them actually don't opt for safety nor chase money - they are confident that money will come to them.