It’s true it takes time to figure out how to connect the blade to the bottom clamp without looking, but once you learn, you will find how easy it is to top feed. No more lifting the board to feed the blade. It is more difficult to top feed when using spiral blades because the down facing teeth and tiny holes. But I don’t use spirals that often. Folks who only use spirals will most likely have to bottom feed. But I tend to cut more fret work than portraits. On average, it takes me 10-15 seconds to move the blade from one hole to the next without looking to connect the the blade to the bottom clamp, all by feel.
Like I said earlier, I used to have a Jim Dandy, but I found it easier to lift the arm and let gravity lower the arm, without having to pull it down.