I have 5, and none leak as long as it's tightly assembled and ALL o-rings are intact and correct.
If the leak is a gurgle type when drawing, make sure the two chimney pieces are tight. And don't over-fill, as that can prevent having enough "head room" to allow space for the vacuum that prevents leaks.
If the leak is out the air intake, it's a sure sign of a faulty o-ring or mis-alignment of same, or a bad seal somewhere. Cover the air intake and draw - if you get any draw at all, you have an air leak.