The FPS Freek CQC
enhances your analog sticks and stays snugly in place. The design of the CQC
is such that it is half the height of other FPS Freeks, so the increase in accuracy is less than some of the other Freeks, and the total throw is not increased by much... but accuracy might not be as important if you're in close quarters combat.
The only two possible problems I can think of with any of the FPS Freeks are issues with them fitting some controllers (although they fit a good many) and storing them safely, if you tend to take them off of the controller when not in use. Mind you, there's not necessarily a need to remove them from the controller when not playing, but if there are small children or animals who may attempt to eat them, for example, you'd want to put them up for safe keeping. Sadly, no storage case is provided and these things are about the size of a bottlecap, so fairly easy to loose.
At around $10 USD, these may seem pricey, at first... especially since you can find controllers starting at around that price (well, not the sturdiest of controllers, but they're out there). The thing to keep in mind, however, is that your KontrolFreeks can be used on different controllers... even for different systems. That's something that you can't do with a cheap controller. Plus, if only one stick needs enhancement, you can use a single pair of KontrolFreeks on two different controllers, for example, you could use your CQCs on the Left Analog Stick of two different PS3 controllers - or even a PS3 controller and an Xbox 360 controller, so you're ready to play regardless of which system you jump onto.
If you're looking for better grip and a slight increase in accuracy and you can keep your toys out of the hands - and mouths - of the wee ones, then the FPS Freek CQC might be just right for you.