Defiance...should I see it?

I didn't think much of it. It was overly dramatized and, in parts, not really believable. It had some passable combat scenes, but Bridge Too Far etc it was not. 

It didn't really have the sort of sombre air of grim foreboding that I expected it should have. I don't mean that it was amateur or juvenile, but something about it reminded me of high school Remembrance Day ceremonies. It just didn't quite ring true.

It might be that the creators didn't really understand how to build tension. There were plenty of missed opportunities to do so in the film, such as when the band smuggles refugees out of the Warsaw Ghetto. This is only barely part of the film, as they just seem to pop into the ghetto, hold a town hall meeting, you see somebody crawl into an opening in the wall, and in the next scene they're merrily walking down a country road. 

Personally, I think the whole resembled a sort of mishmash of character vignettes with the story itself taking a backseat. The acting is actually pretty good, its the script that's the problem.