I think it's a masterpiece of it's kind, but I am a bit of a Kurosawa fan - I loved Charisma and Bright Future (less keen on Pulse though which is extremely overrated).
This sums up my thoughts (far more eloquently than I could) on it:
'Cure is an unnerving and unsettling film. Director Kurosawa proves to be an absolute master at creating a bleak atmosphere that chills the viewer to the very bone. Many subtle elements are combined to powerful effect. Locations are cold, run-down, deserted and dilapidated, characters are enigmatic and painted in shades of grey rather than black and white, the acting is understated and the unique use of sound thoroughly unnerving. Gore and blood are glimpsed occasionally and are presented in a way that is cool and observing.
In what is without doubt one of the purest horror films made in recent times, Kiyoshi Kurosawa unleashes a shadow. It is the shadow of apocalypse, an apocalypse which is not seen or heard, but sensed. And it's creeping ever closer.'