I've looked at them and wondered and mused about one. I have a couple of the little red handle Vic paring knives in my kitchen, and I'm impressed at how ell they cut through a wide variety of stuff. I've touched up tyne serrations busing one of those little Eze-Lap diamond hones that look like a small pen with a pull off cap. It's like a rat tailed file with one flat side. I use the round side to get down in the serrations and it only takes a few minutes to resharpen the serrated edge. When you're done, it's like a cutting machine again. Very good for fibrous stuff like ropes and canvass and food stuff.
I may get a serrated spartan yet.