import hooks (PEP 302) broken in Python >=2.5?

[Josh Haberman]

When reading about import hooks, I came across a blog entry comment
that says:

  One additional thing to note about ihooks is that it's
  somewhat seriously broken on Python 2.5 and newer and there
  seems to be little or no interest in fixing it. It's
  probably worth *always* avoiding when writing new code.

--http://orestis.gr/blog/2008/12/20/python-import-hooks/#c264

Does anyone know what this is referring to?  Should I be wary of
relying on import hooks?

Josh