It depends on the facts of your case. I would advise consulting with an experienced immigration attorney, who would review your previous I-601 filing and determine whether the best case strategy is appealing the decision or re-filing a new I-601.
The reason that many people state just to re-file the I-601 is because appeals can take a very long time. But, each case is different and you can't go by a generalized opinion.
I am not sure if you used an attorney for the initial filing, but I would strongly recommend that you consult one to handle your case. This attorney will review all your documentation and immigration history and will be able to determine what your best course of action.