The Frantic is the ball that always works for me on a struggle night.  That ball is just flat out special and it has bailed me out several times on tough patterns ever since drilling it up a few months back.

As for the ball that doesn't work from the word go, the Track 919C.  It works well on the right condition.  However, it has turned out to be much more condition specific than I thought it would be.  I don't throw it much anymore unless I'm on a tough tournament shot or a specific sport condition.  Even then, I still favor my Storm/Roto Grip stuff in most cases.