I'm happy with mine so far but I know some people have had problems. Here is something they are suggesting over on FPN.
http://www.fountainpennetwork.com/forum/index.php?/topic/212251-not-happy-with-your-ahab/
http://www.fountainpennetwork.com/forum/index.php?/topic/212251-not-happy-with-your-ahab/