Steven -- SDS tracks the entire s&p; faz just tracks the financials. 3x bear funds that track the s&p are bgz and spxu. Leverage increases your profit if you're right and your loss if you're wrong. Also, the 3x funds decay more, especially the bear etf's. You might want more successful experience with regular stocks and non-levered etfs before playing the 2x and 3x etf's. It might work to short the banks, but like V says, it doesn't look like a good play now imo.
What makes you think financials could ever fail? It is impossible for finanacials (banks) to fail in America ever again. There is nothing that a bank can do that would result in any material risk, just not possible. They can commit fraud, make material misrepresentations, lie under oath, conduct business with terrorist, anything that improves their bottomline is 100% acceptable ... simple as it gets. So, why in the world would you bet against any financial institution when they are permitted to do anything without any risks?
Just a small sample to what banks are permitted to do ...
1. Finance weapon sales to terrorists and Dictatorships. 2. Laundry money for Governments that kill children and starve people. 3. Hide money for Drug Dealers. 4. Provide 'wire services' to move money out of the country.