You may find it useful to search the discussion board for some informed discussion about these schools. The differences are not primarily the ranking, cost or international study period.

What are your career goals? If they include staying in Germany after graduation, then you'll probably need to speak fluent German.

My goals are to move from my IT role to something in business strategy or operations. I do speak German, and have EU residency so I don't need to worry about that. I like the idea of having a term abroad to get some international work experience.

Check with employers and on Linkedin to see how these schools place in these kinds of roles, and especially, in specific industries that you are targeting.

"Business strategy" is sort of vague: do you mean you want to work in a strategic consulting function? If so, a European school with strong relationships with recruiters in this field (Insead) might be more appropriate, even if it's not in the country. Although I'm looking at Linkedin now, and it seems like WHU has strong numbers here as well.

I don't necessarily want to go into strategic consulting in the traditional sense, but instead I'd like to work with smaller companies to refine their business strategies and set strategic direction. I'll look at Linkedin, thanks.

Does the Mittelstand use consultants to do that? If so, find those companies and ask them where they hire. I have no idea why they would pay a premium to hire from English-language MBA programmes: they need German speakers, with German networks.