The initial reason we switched from King to Fox, was the excessive amount of seal failures we experienced with the Kings. Fox shocks typically have very good sealing characteristics. I will say that it is good to know King has addressed some of the sealing issues we witnessed early on.
With respect to our Fox shocks, we do see more problems with the smaller hoses on the 2. 0s. The most common leak failure we have is due to people tightening the shock, and bending the hose against the tower(stem top versions). Usually not the shocks fault. With that being said, there are numerous ways a shock can leak, and the can all be addressed quite easily.
Get this, we have also been known to off road, pre-run, chase, and even race a little without them Fox's leaking either. Amazing, just like Bob4x4. Ha ha.
KP