i have been using the 1700mah of the same battery, only issue was when i originally got it i charged it on lipo mode with a new charger (rtfm!!) and it peaked at 8.4 like a lipo. i tried to run it but it would die after 2 tanks. in the process of returning it i thought to drain it some and try life mode with a lower voltage. in life mode the charger would read over voltage and cut off. i drained it about 1/2 way then re-charged it in life mode and it has been fine since. the 1700 will easily do an hour main and they charge quick too, unlike lipo they charge at 1.7amp longer and only trickle the last 100mah or so. as far as the voltage goes for servos, a fully charged 5c nimh pack can reach 7.8v, the life peaks at 7.2v. so any servo that can run on a 6v nimh is definitely safe to run on a 6.6v life. in my opinion with the safety and durability of a life pack there is no better option fro an rx pack. and they can be balanced so unlike a nimh you won't have 1 bad cell ruin the pack.