Let’s be clear what the OP is speaking about here. The Planar 6 RS edition jettisons the RB303 arm for the RB808 arm used on the Planar 8, likewise the sub-platter is the all metal device which sports dual drive belts also from the P8.
Does it sound any better than the P6 or as good as the P8? Never having heard one, I have no idea, though I know what it is. And no "RS" does not stand for Radio Shack.
My take is that the P6 appeals to someone looking for a traditional form factor within the Rega line, so this is an attempt to push that performance closer to the P8.
Having worked in the industry for well over 20 years, I can say that my personal preference, sonically - and a personal preference it is - is for a phonograph over a digital source, YMMV.