I lived in Germany for 2 years - one during my Jr. year in college and a second between undergrad and grad school. I loved living there and have no regrets, but didn't have a family with me which significantly changes the math on something like this. I don't necessarily agree with the comments that most Germans know English. That is not true in my experience, at least not as compared to places like Holland or Sweden, where even blue-collar types typically speak passable English. In Germany, university grads and professionals typically speak decent English, but most people you encounter - for example in retail, waitresses, barbers, bartenders, cops, etc., and others you interact with on a daily basis just getting #### done - typically do not speak English.
HOWEVER -- both Ramstein and Weisbaden are big US Military enclaves (both near Frankfurt), so that kind of changes the analysis. I didn't spend time in either city, but my understanding is these areas are much more geared toward Americans, just due to having tens of thousands of US military there, in many cases included spouses and kids. This can be good and bad. Good, because your family is likely to be able to find other Americans to associate with, find American food, newspapers, etc. In general, the cultural transition is probably softened quite a bit compared to living in someplace like Hamburg or Berlin. The downside is that its hard to get immersed in the local culture when surrounded by ex-pats from your own culture. Kids are less likely to learn German and integrate into the culture if they don't have to. They won't play soccer if there's a local American football club stocked with American kids. And, in some instances, I think there is sometimes some degree of animosity toward Americans in these areas. Its something to look into and ask about. You can imagine if there were 20,000 German soldiers living somewhere in Kansas, a vestige of a prior generation's military and political humiliation and shame, with soldiers doing what soldiers do, the locals might not have an entirely unbiased or positive view toward Germans in general.
I recommend doing this and would love to have the opportunity myself, but it is worth considering how flexible your family is, as there will likely be an adjustment period and some difficulty with the transition.
