I have the woodchuck and logrite log jacks. I think log jacks are overrated. It seems you only get 2-3 cuts then you have to reposition the jack, 1-2 cuts, reposition jack, repeat. Just cut the log 2/3 down, roll it over, finish your cuts. For big logs I use the log rite cant hook to turn 'em.
I agree, and that's why I don't use it as a lift that often. Sometimes the lift is valuable, though. I've used it to lift logs out of muck and pull it away from brush and vines in a much more effective way than just a cant hook. There is the log on which I only need to make one or two cuts to make it more manageable for moving, and the lift function shines here, too. Most of the time, however, I use it as a cant hook or peavey to roll the log.