RE: LiFe or Lipo with regulator??
No matter what battery you use (and ALL of the above work great). It is important that you learn everything about the battery of your choosing.
Pay attention to the numbers that the charger gives you both at the beginning of a charge and the end of the charge.
Keep track of how many flights you flew vs how many mah it took to recharge.
Check your batteries between flights.
You do this and battery choice will be the least of your worries.