I have seen a thread on RCtech where a Maxamps rep has called Turnigy cells factory seconds, rejects and low grade cells from the same production line (which kind of buggers up the 'you won't get our cells from any other manufacturer' bit).
To set the record straight, Hextronics/HobbyKing purchased the factory where the Turnigy brand battery is produced about three months ago. The Turnigy brand batteries are not seconds, rejects, or low grade cells.
The two main things that make a good lipo cell is the purity of the mix and how long they are in the oven (baked).