There are two reason's why everyone wants FKS: They are orange and they look cool. Yes they are durable and reliable, but honestly how many people break their bindings on the regular? I personally am not a fan of dildo style heels as they do not release as smoothly as STH / Mojo styled heels, and they are a pain in the ass to click into in powder.
Positives -- Very durable, great elasticity, safer turntable heel, very short mounting pattern that allows the ski to have a more natural flex
Negatives -- Pain in the ass to click in in powder, pain in the ass to click in on any sort of slope, very difficult to replace brakes, brakes snag and bend very easily, narrow mounting pattern, heels prone to tear outs, very small adjustment range (if you get new boots in a different size, remount is many X more likely)
After tearing my ACL twice, I do not need all the elasticity that the FKS provides. I have replaced mine with the Mojo 15. Many people complain that the toe piece is shitty, but I personally think it is a very reliable toe piece. Also resale value is not as high as you would expect for a binding in such demand. If you are a fan of the dildo style binding, this is by far the best option out there and I would highly recommend it. I personally would only recommend them if you are a III or III+ skier. No beginner or intermediate skier needs this amount of elasticity. Do not buy them because they are the cool thing to have. For everyone else, these bindings will outlast many pairs of skis.