It's like firing with a water hose! The extensions make the stick WAY more sensitive. I thought that would be a good thing, but no. They make the crossover from aimimg slowly, to looking around quickly, smaller. If I need to adjust my aim more than a little, I end up wildly looking around.
The thumbstick extensions are comfortable and durable. They might work well on other games or for other people. After 4 days of playing with them, I took them off and I'm getting triple the amount of kills per match.