For what it's worth, I had my 1.0.3 file in Applications and when I unzipped the Beta it was automatically named "SliceAndDice 2" and wouldn't launch (even after I confirmed that I wanted to open an app from an unverified developer). I renamed the old app to "SliceAndDice 1.0.3" and the beta to "SliceAndDice" and then I could launch the beta.