I have one in pretty dense shade (it is under the canopy of my woods, never gets direct sun, but gets dappled sunshine intermittently). I only planted it last fall, so it is too soon to tell. My friend at the botanical garden said it should do okay in that spot. I am glad to hear others have had positive experiences with it.
I am always in favor of things that spread and reseed, so long as they are native. I do, however, have mixed feelings on the subject of poison ivy and blackberry brambles which are native and wildlife friendly, and like to reseed in my woods. I would rather have ninebark!