I don't understand why JeV has been overlooked not once but twice by Red Bull. He beat Ricciardo in 2012 and trounced Kyvat this season.
Well if we look at points, sure, but points do not show what a driver is capable. Put it this way if a one driver smashes the other in qualifying and finishes ahead of him in 18 races to 1, but that single race the other guy did well in was the only race in which the car was capable of finishing in the points you would end up with a crazy points difference but no reflection of that.
For reference
http://grandprixrankings.com/compare/2012-f1/ricciardo-versus-vergne/
Ricciardo out qualified Vergne 15 to 5, he finished ahead in races 8 to 7. It's not full proof to exclude results when either driver has had a DNF, some are caused by reliability(some of which can be driver fault also, pushing too hard, not watching temps) and some are caused by being hit by others or causing a collision.
http://grandprixrankings.com/compare/2013-f1/ricciardo-versus-vergne/
What about 2013, well Ricciardo outqualified Vergne 15 to 4, finished ahead in more races(the car was less reliable so less comparisons and I wouldn't read loads in to it). Ricciardo ended up with more points.
Across both seasons Ricciardo beat him in every category, less DNF's, thrashed in qualy, most points overall, finished ahead more often. RBR chose quite clearly the better driver.
http://grandprixrankings.com/compare/2014-f1/vergne-versus-kvyat/
Kyvat in his rookie season at a very young age out qualified Vergne and in race it was only 6 to 5. Again as with Ricciardo you can see something about him when he races. He made passes on top drivers, was aggressive without being out of control(mostly).
Kyvat for me looked to be the better driver, just less experienced. Vergne at this stage has also been in the car far longer and is far more used to the team, his engineers and the car itself. I suspect that had it been Kvyat against Vergne for another year he'd have done better and beaten Vergne much like Ricciardo did.
Ricciardo spanked him pretty bad and Kvyat showed his potential by basically matching him, Vergne has shown almost nothing by this stage. Decent driver, sure, not a great driver and absolutely no signs of it either.