TX Battery, Lipo or LiFe?

[MRD]

I think the Nimh pack in my 3pk is on its way out so I've been looking at getting a lipo or Life pack instead, but i have two questions,

Does the voltage difference play any part, 11.1v Lipo Vs 9.9v Life?

With the 3pk having no type of cuttoff, whats the voltage when it starts beeping using either type of pack?

I'd imagine the Life will be safer but it's 1600mah where the Lipo is 2300mah but more critical with over discharge.

Not sure whats best to do

Any thoughts?