Pros: Lightweight and strong. Convenient Velcro band for storage.
Cons: Cable ends are too bulky to allow the cable to secure a saddle.
What can one say about a security cable? This one is lightweight and strong, and has a convenient Velcro band attached for easy wrap-up and storage. Kryptonite claims that its braided steel design is "more resistant to cutting" (presumably sawing - see below).
Note that a cable should NEVER be your first line of defense against bike theft. As if to stress that point, this cable does not come with a lock. It is intended to be used as an adjunct to a good U-bolt lock. I use a U-bolt lock (a Kryptonite Evolution 2000, for which I've also posted a review) to secure my frame and one wheel to an immovable, hard-to-cut object, and my KryptoFlex cable to secure the other wheel. This is more convenient than removing the wheel and locking it to the other one and the frame with the U-bolt. If I have to park briefly in a place where there's no convenient rack available, the cable makes it possible to lock up to a tree with a trunk thick enough to discourage thieves. These are not the most secure ways to lock a bike, but they're good enough to foil casual, opportunistic thieves.
Remember, though, that all cables are highly vulnerable to bolt cutters. If you're parking a bike in an area where more sophisticated bike thieves, who carry such tools, are known to operate, you'd be best off securing your frame and both wheels with U-bolt locks, and using the cable (if you use it at all) to secure other easy-to-remove components. Alas, the most obvious cable application in this case is to secure the saddle, and the KryptoFlex cable's bulky end loops and collars are too large to fit through saddle rails.