While it's nowhere near the league of Hitchcock's masterpiece, this sequel is entertaining enough in a cheesy sort of way - even if it really is nothing more than a slightly above average slasher movie. Anthony Perkins turns out to be a fairly competent director, even if he is a bit past his prime as an actor.
This third installment of Psycho (directed by Perkins himself) is actually surprisingly good. Psycho 4 is also worth checking out (as long as you ignore the contradictions and minor potholes each sequel provides).
Anthony Perkins was actually a very good director! (Interesting stylistic choices throughout!) The PSYCHO franchise (parts 1 through 4, anyway) is actually one of the better Horror franchises out there. The sequels are all in the range of JAWS 2 ... unnecessary and inevitably overshadowed by the classic original, but ...surprisingly ... pretty damned solid!