I've been using all Seaguar's products for years in tournaments, on spinning and casting. They each have a purpose. For instance, Carbon pro has less shine and is good for gin-clear water.

As far as breakage, I know a lot of guys that give up on fluorocarbon b/c they think it just "breaks" at random. This stuff is sensitive to the slightest kinks, and sunlight. If you get even a small kink (e.g. from a backlash), you might as well cut it off. Kinks can happen easily while loading your spool with new line, if you're winding too fast, or not paying close attention; particularly on spinning gear. Hence, the feeling that brand new line is randomly failing.

Knots: If you've been using a section of line for a while, try cutting it off (15-20ft) to get knots to hold right. Knots won't hold on fatigued fluorocarbon. Also, your knots must be absolutely perfect and wet when tightened. You won't have much luck using a sloppy tying technique you can get away with using mono.