itlogic ref. the FAS, FAZ dilema they seem to change % drop or increase every few days, I have had both in and out for some time but haven't had FAZ for a couple months now.
Though you can lose up to 40% in a day you may well gain it back in a few more days to break even, but shorting now is chasing a train you are right on that.
Like you said shorting when the Fed is supporting the sector, doesn't show much promise as a trend, though it may on a given day. For now the volatility is quieting down a lot, but the trend is gradually up unless the apple cart really gets screwed up.
Good luck, but my money is with FAS/UYG/DXO until something changes