the only ETF i''am holding now is USO.i feel so cheated cuz i bought the fund when oil was trading at $36 per barrel and now oil is trading at over $45 but i''m barely making any money on this ETF.
It can also trade above or below net asset value, which can cause a failure in tracking. These anomolies should not last long though.
I read GLDs disclosure; it makes you prefer to own the physical gold. Lots of odd things especially regarding insurance of the gold they hold and their limits of liability.