Time-series and specifically ARIMA type of models can have great results as long as the details are understood. Don't model blindly or the results will be unstable over time.
Uses and Abuses of ARIMA in PPNR Modeling and Risk Management: Why Not to Fear ARIMA:
http://www.garp.org/#!/risk-intelligence/detail/a1Z40000003Kw7BEAS/uses-abuses-arima-ppnr-modeling-risk-management-why-not-to-fear
The Financial Modelers' Manifesto:
http://www.uio.no/studier/emner/sv/oekonomi/ECON4135/h09/undervisningsmateriale/FinancialModelersManifesto.pdf
