I agree, except that a system in which the jacks can be stowed when raising the main are even better, such as
E-Z-JAX Systems 
From their website:
The patented E-Z-JAX sail control system retracts neatly and easily below the boom when you are not using it. Most lazy jacks are designed to be left up all the time. Why is this unique feature so important?
- Eliminates chafing - Your E-Z-JAX doesn't touch the sail while you are sailing.
- No sail or sail cover modifications - Your E-Z-JAX will fit neatly under your existing sail cover.
- Eliminates battens catching - Leave the E-Z-JAX retracted when raising your sail, no problem.
- No interference with awnings - The retracted E-Z-JAX is out of the way for above-boom awnings.
The E-Z-JAX System has up to 4 lines on each side of the boom, depending on boom length. Most lazy jacks have only 2 or 3.
MORE LINES = BETTER CONTROL