i really like them! however, I would love for them to be ADDED to the current clicky types available, not to purely REPLACE the old ones. Admittedly, though, that is more for nostalgic reasons than practical ones. I don't want to see the classic clicky form disappear completely.
disadvantages I can foresee: not as easy to stand the clickies, particularly in large rows/regiments if making armies, because the legs/knees will have to be accurately posed in order to get the clickies to stand. For me, I would prefer the classic bodies to use for mass armies and cannon fodder, but use the articulated clickies for specific poses (like kneeling riflemen, trench crawlers, etc...).
major advantage besides better poses, is it opens a bigger array of possibilities for stop motion films. Until now, stop motion clickies "glide" along the ground as if on roller skates since there is no way to make them walk without articulated legs.
I wonder, though, how easily they can be disassembled for customizing. I doubt the hans beck method will work for disassembly.