It's the same core editor with different pre-installed plugins, so I think criticisms of any of the JetBrains IDEs often apply to all of them. I have indeed seen slowness (depending on context), graphics issues, and focus issues in WebStorm, PyCharm, and others, but I still like them better than any other editor I've used.

Every language has its own implementation of code intelligence, though, so for different languages you might see significant differences in things like indexing time and the performance and quality of autocomplete.