I have the two-stage version and they are magnificent. If it helps, I rarely expand the second stage, and for nature/skiing this works great; fully extended it comes up to about head level. I don't see the reason in paying another $300 to get the camera another 8" off the ground, especially considering how little you'll need that height. And in the off chance that you do, you can just use a hi-hat + ladder, jib, tree, whatever, and put the money you save towards something more economical.
Also, the longer you extend the legs, the less stable it will be. My two-stage is solid fully extended, but I feel that three stages would be pushing it.