I thought Jones played well for England against France. If he was capable of keeping up that form I would certainly keep him in preference to Smalling who is seemingly in JM's bad books. Jones seems more versatile (and has been pointed out - readily able to bring the ball out from defence) whereas Smalling seems very 'one-track'. One of them has to go, my vote is for Smalling to go - shame, as he had a blinding season for us a year or so ago but her never maintained that form.
Smalling for me. Jones has a grit that Smalling lacks. If both were fit, I would always pick Jones over Smalling.
Smalling to go 100%. He's decent, and has done well enough over the years, but has plateaued at a time when he should be pushing on and reaching the peak of his career. Jones is a couple of years younger and better in the tackle and with his feet. If we really want to challenge for the title we can't have Smalling at the back, he'll cost us too many points. Whereas I think Jones could do alright alongside a more assured presence like Rojo or Lindelof.
Smalling was quality under LvG as you played with a man marking system - under Mouriniho you play with zonal marking and he is more exposed unlike Jones who excelled.