Having done my doctorate in both the U.S. and Germany, I can vouch that this is indeed not uncommon. However, you will likely have to "start from scratch" in the U.S., since most programs are a masters/PhD rolled into one. I knew many European students, with European masters already, who spent two years more than they would have liked taking classes and passing exams in U.S. doctoral programs, before they could start real research.
You have to also consider your long-term goals. You're more likely to get a job where you've spent time building connections. If you want a job in the U.S. long-term, then a Ph.D. there would be good; if you want to return to Europe, however, then it's probably better to get the doctorate in Europe. You could of course also consider exchange programs, visiting a professor for a few months, or a dual degree if you'd like to get a mix of both.
To more directly answer your question: of course it's possible to get into a "really good" U.S. graduate program with a masters from Germany. But "really good" is ultimately relative to where you want to be, what you want to do, and how novel your own research is. Rankings and perceived prestige don't matter nearly as much when you're competing for jobs and trying to settle down somewhere.