The following should explain pretty much everything about the models. It's some lengthy reading, but it will help to explain each model's strengths and weaknesses. I would also like to point out what scottsvb said earlier as well as what Ed's "credo" is...anything beyond 5 days out is pure speculation.

model explanations

This needs to be watched...closely...and everyone on the entire east coast and probably for now the Gulf should monitor Frances' progress. But this storm is still a long way away from the US mainland. For now, don't take what the models are predicting past 120 hours (and more realistically 72 hours) as anything but speculation.