I have Harris pods, and one thing I have noticed is, on the notched leg models in it's lowest position there is 1/8th to 1/4" of spring loaded travel that depending on the weight of your rifle could magnify upward movement. If the rifle is of the weight to just compress the spring loaded slack, it is sitting there ready to jump with even the slightest help from the recoil. The non-notched models have a friction lock you can tighten down and all slack is removed.
I have no agrument that shooter form is of huge importance here, but in some field conditions you have to deal with what is available for the shot. I really like the convenience of the spring loaded notched legs that are quickly sprung out to meet your needs, but I feel the friction locks for the legs on the non-notched modles make for a more sold rest.