The photography is undeniably great, but watching the evolution of a highly despicable character for 3 hours is a bit annoying, all the more as the plot isn't that great (it's pretty mechanical and predictable especially in the second half - cf the chapter titles). My least favourite Kubrick film with Eyes wide shut.
Kubrick's flaw is probably a (strong) tendency to be overly technical on the expense of the humanity of his characters.