I realize that the OP may be home by now, but we have just been to Warsaw, Lodz, and are in Wroclaw now. My observation is that Wroclaw is attractive but overrated and too “rebuilt.” To understand what I mean, consider that the Old Town in Warsaw is a UNESCO WHS and the Old Town in Wroclaw is NOT. They were both completely rebuilt, but the latter looks like the Disney Imagineers just finished painting and left on schedule. (Sorry! That’s mean, but I’m entitled to my opinion.) Even Wroclaw’s small and out of town UNESCO site, Centennial Hall, is ... meh! The best part of Centennial Hall was seeing the local families enjoying a summer Sunday.
I thought Lodz was fascinating, and I’m glad I saw it before the gentrification goes any farther. (If they are lucky and their economic recovery continues.) Like Poznan, you may need a personal reason to go to Lodz. But it might not have to be, as in my case, “Jewish Grandparent Tourism.” If you’re from a dead textile town north of Boston or Charlotte (or London), you might find Lodz FASCINATING! It also has lovely (if, some, abandoned) 19th Century buildings.