1) One advantage of skegs over rudders is foot support. I much prefer having my feet planted firmly on an unmovable surface. If one is doing much edging, a big advantage.
2) One of the big drawbacks of skegs is their getting jammed with pebbles. There is a simply solution to this: put a piece of duct tape over the skeg opening, with a piece of string/thin rope secured to the aft end of the tape. Run the string up to the bungee just forward of the cockpit. After launching from the beach, pull the tape off with the string. I've been doing this for a while, works quite easily. Other than getting jammed by pebbles, skegs should be quite reliable...just don't leave them down when landing or in very shallow water.
3) Sterlings Kayaks has a wonderful advance on skeg designs...they call it a skeel. It sits just behind the paddler, so it tends to stay submerged when on steep waves, and it doesn't inhibit turning much while deployed (unlike a stern-mounted skeg). They also designed the wire in a way which is really kink-proof: the entire length of the wire is always fully supported. If you were to run aground with it deployed, it would just push the wire/control forward, with no kinking.