I bought 32 GP3300 cells from somebody who uses them for world level competition flying (not helicopters). They were only used 5 times, and they were selected from a bigger batch, matched and pushed (something about giving each cell a very high voltage for a very short time - not all cells survive this).
If you want flight times over ten minutes Lipos are really your only choice.
My first flight with this pack in my Joker CX got me 10 minutes
(and a few seconds) of light flight (hovering, circles, pivoruettes, ...).
Standard Actro controller and 24-5 motor. Pinion and headspeed i do not know, but I can check if somebody wants to know.
I month ago I bought a used Maxi Joker from ebay.de. I have not got it airborne yet, but can I expect longer flighttimes on this bird using the same packs. The Maxi has the same controller and motor.
Minicopter 3D and 3DD, TDR, TRex 700E (and a full size 90.000 cubic foot hot air balloon)