Thanks for the replies!
I am certainly a makiwara purist, and am reluctant to purchase it. But it is much cheaper than the floor platform one, and sounds like it can have much use up to a certain level of power. I can cetainly say, however, that my fists have been aching to strike the old makiwara
(I've been away from home for a year). I'll have access to my old outdoor makiwara over the summer, a good old one made from an actual whole pine branch with a natural taper,
and will reconsider the purchase later this summer.