RE: Yes it's true...
Even the smallest gar will cut dacron, or at least fray it, on shoot throughs. You will never catch me shooting anything but Fast flight. Besides, dacron is elastic and loads up like a rubber band, so is susceptible to snapping back. Fast flight cannot handle a sudden shock load, so will break. It isn't just the famous snap back either. I know a guy that was hung in a root, and pulled big time on it (with dacron). When that baby let loose, it rubber banded all the way back to his nose and took it half off.
IMO, Dacron is an accident waiting to happen, and I cannot find any single good reason to use it over fast flight (or similar).