For most desireable 686 I'd vote for the scarce CS1 variants.
I would have agreed with this as I have a 4" CS1 and it is an excellent gun. However, I have since acquired a 586 L-Comp and it has become my favorite shooter of the L-frames. The stainless version of that (686 Mag Comp - I think) would be the best one in answer to the OP. YMMV!