In the part where you state the difference(s) between the DWS779 and DWS780, you say that the main difference is price (partly justified by the shadow light system) but there are actually other differences too, which (to me) give the 779 an advantage. The DWS779 has a 5/8″ arbor where the DWS780 has a 1″ arbor. The 779 comes with an adapter to convert 1″ arbor blades to 5/8″ so you can use either size on the 779 – the 780 having a 1″ arbor and the lack of an adapter that would somehow scale a 5/8″ arbor blade up to 1″ means the 780 can only take 1″ arbored blades (less availability and options).