All accounts of his life describe him as ruthless, but only the ones originating from his Saxon detractors paint him as sadistic or insane. That said, Vlad was a bit over the top, even for a very violent era.
Romanian folklore and poetry, on the other hand, paints Vlad as a hero with a reputation in his native country as a man who stood up to both foreign and domestic enemies,
Vlad was nominally a Christian, although there is little evidence that he was any more religious than the average despot of that era.