I'm long BIL this week, been in and out a couple of times. Comments on summit and others are regularly saying BIL is a better long term proposition than AGL, so I go long whenever price weakness sets in. Nothing too scientific, but it has worked well for me. If it does go the wrong way, I am prepared to sit on the loss as I believe it is a good share so will recover eventually,
I believe BIL has already broken support going back to Nov'08. We can see a retracement to 190 to close the small gap in price but then it's down to maybe test the lows. A close below 180 will confirm this.