I guess it all depends on the care and feeding of your battery pack with regards to its longevity and performance.
Thank you for your replies.

Captain Larry, I have bought cheap lipo's and expensive ones, over 2 years i have not found much if any difference, there was an item on How its made, they said there was only a few manufacturers in the world, so it might be just badge engineering??? or lower grade cells, not fully matched etc.
Have i been lucky? i have not had any failures.
I will say that i only charge at 1amp regardless of the C rating.
Regards
Mark

Hi Capt Larry
I have used the Turnigy and Compact Zippy ones from Hobbyking with no problems for the last three years.
Note only charge them at the maximum current equal to the battery capacity, eg 5800 mah = 5.8Amps.
Lower Amps is better.
Canabus