I am a mathematics Ph.D student in the United States, and recently received a 3 year postdoctoral offer in Germany, which I have only a few weeks to accept or decline. The offer is very good (high salary, travel funding, no teaching unless I want to) the PI is basically the top person in my field, and the position also solves my 2 body problem (my SO has a similar offer from the same place), so I am tempted to accept it.
However, I have sometimes heard that an American doing a postdoc in Europe is at a disadvantage applying for permanent jobs since European positions are often restricted to EU citizens and American schools are less likely to hire someone who did a postdoc in Europe. Can someone (on either side of the pond) offer perspective on whether my concerns are valid? I need to accept or decline the position before offers for US postdocs are sent out.