I wonder who wrote this question :-)
As you correctly state, I am an alumni of WHU (www.whu.edu), and still have a tight connection with the school. That probably puts me in no good position to answer the question in an unbiased fashion.
I can, however, give you two points of advice on how to figure out what the best school is for you:

1) For a good overview of the available schools and their characteristics, look at the available rankings, e.g. from CHE (http://ranking.zeit.de/che10/CHE) or Handelsblatt (http://www.handelsblatt.com/politik/bwl-ranking/). From there, surf the schools' websites, get a first impression of how they portrait themselves.

2) Go there. Make a list of the schools you can really imagine yourself attending. Look up when their "Tag der offenen Tür" is (open house). Go there. If they offer it, stay with a student, don't go the hotel route. Use the day to the fullest - and talk to people as much as you can. Nothing gives you a better glimpse of how life at that school will actually be.

3) Trust your gut feeling. Or, if that rings better with you, follow your heart. Everything else makes you waste a lot of time and money going in the wrong direction.

Hope that helped! If you have further questions, don't hesitate to email me at contact@killerconsultant.com.