Is swaddling good or bad for baby?

My health visitor just told me that new information advises against swaddling newborns as it hampers their startle reflex and when they are too cosy they are less likely to rouse when necessary. I always umed the opposite with swaddling, that it was beneficial and comforting to the baby. I tried a gro-bag as she suggested but now baby won't settle at night. Anyone else been given this new advice?