id see the knobs as being more in the way then the system my hardtop uses. with the knobs you have the knob brackets visable when the top is removed. and when i have rear passangers they use the ledge their for an arm rest and i would see the knob brackets being in the way of that.
the top i have just has the clips at the back, sitting just by the seatbelt towers. when the top is off its very clean looking setup and even with the top on it looks great.