Dave,
I never have on the LRF, but I use the Duracell "Ultra" in it, the GPS, 35P, headlamps and anything else that hits cold weather or needs to last a long time. The voltage seems to stay higher on them and life is almost exactly twice as long. I also carry HALF as many spare batteries in my bag as a result!
Why they last longer, or the voltage stays high enough my GPS don't turn off is beyond me, but they work really well. This Lithium battery in my Nokia lasts about 5-7 days, gets left on 24/7 too. I've had this phone here since July, and it don't get plugged in unless it starts hollerin at me to charge it. Charges in less than an hour too!
MTBA,
Any idea why the Ultra's keep voltage higher and last longer, when in the same size package and both are alk's?