I read the reviews on both this, and the gioteck triggers. and opted for these.
Slip on easily, and come off just as easily when attempting to do so(not with normal playing). They even stayed on when I dropped my controller.
The biggest flaw with the ps controller is cleary the L2/R2 triggers. They are very poor, and not suited for any sort of game where they must be held in for continuous periods of time (think racing games). Thankfully, these improve the triggers for games where you're holding the controller in the same position for a long duration as there is npw no chance of your finger slipping off the button, due to the poorly designed controller.
However for games that do require movements (action, fps's etc) I occasionally pinch myself when pressing L2/R2 due to me holding the controller differently when playing these types of games, when compared to racing games.