Lübeck is probably better for a start, to get an idea of this culture and architecture which is notably different from other parts of Germany. Despite World War II damages the old town is well preserved resp. repaired while in Wismar there is still a lot of work to do, as the big repaiirs only started after the reunification (with the exception of the market square). Unfortunately two of Wismar's three medieval churches, which must have been as impressive as those in Lübeck, were destroyed. The third is still there but in bad state, one is being rebuilt but still empty inside, of the third only the steeple is left. Wismar is easier to appreciate if you know a bit about what you are seeing.