I have only been flying jets for 9 months. My experience in those short months goes back further to 27 years of flying Scale Aerobatics. What I learned previously, followed me forward into jets.
On the turbine side of things, I asked a lot of questions prior to settling on what I'm using now. My initial plan was to use a PowerBox LiIon 12v battery and then a regulator. However, it was highly suggested that I would experience issues with the ECU & turbine, if I went that route. I settled on using the KingTech 3800Mah LiFe 9.9v for the ECU/Turbine.
For the servos/controls, I have been using the PowerBox LiPo 4000Mah through a PowerBox Mercury and they are regulated (using the PowerBox) to 7.4v output. I've had 55 flights and have never experienced low voltage (either with the ECU or the PowerBox) during flight. The most flights I have ever done in one day was 6. Usually It is between 2-4 on any flying day.
This year, I have some new PowerBox Li-Ion 5000Mah which I would like to try out in my new jet (Leonardo again).
Wayne