Not quite as good as his Suicide Squad or Spectre, but not the worse series I've read either.
There was a nice MM/Spectre team-up in one of the "flashback" issues...
But, the series peaked too soon with its zero issue and 1 Millionth issue coming out (those were great...but, after that...what story was left to tell?)
The series suffered a little bit because it seemed the JLA writer never bothered to check what was going on in the MM title (as the current JLA writer didn't as well...)