Is KRDS to KDS/1 worth it?

Now that I have got my system back to a KK/1 & KTC (D) & 212's am now considering a KDS/1 as there seems to be some good prices to be had..

Is the improvement from a KRDS to a KDS/1 significant ...I have not heard the two side by side so will need to rely on feedback from someone who has...

As usual any feedback appreciated...