> ... get less than 1% spam,
  > handled by gmail spam filtering.

I'm starting to see more and more reports of people having their emails automatically go to gmail spam folders, unless the emails are coming from gmail itself. I've seen both sides of this - gmail regularly bins emails I sent from a non-gmail account, and my gmail accounts regularly bin genuine emails from non-gmail accounts, but apparently never from gmail accounts.

It's almost like there's a pervasive force, trying to make people use gmail.

I, for one, don't trust gmail at all any more.