The other advantage is the shelf life of the charge.
The NiMh will self discharge about 5% a day.
Once it gets down very low you need to reform the
battery to make it usable again.
The LiFe will hold its charge for a very long time as
CG reported at the beginning of the thread.

The advantage of LiFe over LiPo is the lack of volatility.
It is recommended removing LiPos from their devices
to charge in case they decide to burst into flames.
Rare occurrence but documented.
LiFes do not have that problem.

I will be switching to them soon for my receivers.

Good Luck,
KW_Counter