That delay is because it's storing the undo information.

And P7 inculdes all P6's advancements, the affore mentioned one, point lights, much imporved lighting and opengl display, multithreading for dual core (or more processors), and the morph brush tool, which is great for fixing minor stuf, without resorting to magnets.

I can't even stand going back to P6, and can;t imagine having to go back to P5 any more.

Once you get used to new tech, going back is always difficult.

Way too many people take way too many things way too seriously.