I have the same problem too. My left joystick doesn't work too perfect. it SOMETIMES works and SOMETIMES doesn't work.
I don't know if I'm unlucky this time or not, but I have NEVER experienced this problem with my ps2 controller..NEVER.

Within buying the ps3 and the controllers in 3 months, this is absolutely not acceptable on a consumer's point of view.
very disappointed...hopefully, DS3 is gonna be better.