Guten Tag,
while I am no expert about German B-Schools, I am somewhat familiar with the country.
As others have already mentioned EMBA options, I´ll go a little more into detail on some of the MBA programs you mentioned.
Just a quick side note; While IESE is a good school, its main facilities are located in Barcelona and even if they offer programs in Germany their alumni network and brand recognition is nowhere near as strong as it would be in Barcelona/Spain.
When it comes to working in Germany in particular, I would take Mannheim and WHU over most European Schools (LBS, INSEAD, Oxbridge, IMD being the main exceptions, one could argue St. Gallen) for the reasons mentioned above (Alumni, Connections to German Businesses, Brand recognition in Germany).
If you have the choice among WHU, Mannheim and Frankfurt (I assume School of Finance as opposed to Frankfurt University?) I´d opt for either WHU or Mannheim.
Pros WHU:
Relativly small, private school, very good connections to German Business especially in the fields of Consulting, Finance & generally strong presence in the Startup Scene.
Contra:
As it is not a public university, it might be less well-known in some industries as compared to Mannheim.
Pros Mannheim:
Large, well known university (in Germany) and considered the premier place for Business & Economics.
Contra:
Very competitive to enter (lower admission rates than Judge, Said, Insead, LBS etc.) according to what I have read online.
That would be my assessments in a nutshell, if you have any additional questions, feel free to reach out.
Viele Grüße,
Chris
_________________