> Trains from Switzerland are more punctual than trains from Bavaria. If you are in the southwest and need to go north (Hamburg, Hannover, Berlin, Ruhrgebiet), the ICEs that originated in Zürich or Interlaken are noticeably more often on-time than the ones that came up through Munich. Why this is so I cannot fully prove. Given a choice, pick the Swiss-origin train. The same applies, more weakly, to trains originating in Austria.

Besides them being from Switzerland, that is actually pretty easy to explain: International trains have priority over national ones and as such are less likely to get delay assigned by the scheduling administration.