I did my first postdoc at the MPP. In general, I think it is a very nice place to be and there tends to be a relatively good flow of good people coming through (now, the postdocs and PhD students that were there at my time have left, but I think it is a general statement). Of course, it also depends on who you go with and what your interests in physics are and whether or not you find a supervisor with those same interests. The location is perhaps not the best in the sense that it is not central as the LMU or at Garching, where you would get some synergies with other institutes and TUM. Is there anything particular you are wondering about?