Option Millionaires

[iwjw]

Some opinions needed...
I made a performance comparison of FAZ with FAS over a 3 month period and got an interesting (but not astonishing) result:
http://finance.yahoo.com/echarts?s=FAZ#chart7:symbol=faz;range=3m;compare=fas;indicator=split+volume;charttype=line;crosshair=on;ohlcvalues=0;logscale=on;source=undefined
If one would have played both ETF with vertical credit spreads in Nov/08, there would have been good money to be made, because both ETFs are down huge
So I'm asking myself whether this behaviour can be prolonged into the future and a good trading opportunitiy unveils with high leveradged ETFs
A few weeks ago I read a very interesting article about leveraged ETFs and that you never should hold them longer than a few days
I found a link to this article in an IHUB post, but don't remember which board.
So my question is:
Are those 3x leveraged ETFs doomed to fall in a longer timeframe because of their nature?