On our way to Cologne from southern France, we have the opportunity to visit one additional Christmas market and overnight in that city (we will be driving). We are trying to find whether Metz offers a great market, or if we should be looking at either Karlsruhe or Heidelberg, Germany. We will already have spent time in Strausbourg. Any thoughts that folks can share would be appreciated.
The market in Metz is great! I cannot compare it to Heidelberg or Karlsruhe as I do not know those, but it is a very good one, and Metz is a very interesting city to visit.
However, if you also want to visit Alsace as per your other posts, it lengthens your total driving time by a few hours.
I've recommended the Metz Christmas market to friends a few times, and all have come home with great memories.