Not too scary in my books, there was a handful of sudden jumps, but these quickly faded. It's only scary once they start ripping and screeching their stringed instruments!
It certainly wasn't a movie that made me feel weird (scared-type) walking out of the cinema afterwards, and the plot was nowhere near enough to cause that 'haunting' effect that lasts a few days, for examples, movies like Paranormal Activity (1 ONLY!!), and The Exorcist.
Go watch it, it's nothing bad tbh. 6.5/10