TLDR; If you discount everything cause steroids then none of this matters but JJs body of work is better than DCs in every way. The only argument is Title defenses vs Champ-Champ OR Steroids vs JJ beat him twice.
IMO treat steroids strictly by the rules. JJ got caught and has a NC because of it. Everything else stands.
Let see:
Jon Jones- 24 matches, 22w-1l-1nc
Daniel Cormier - 23 matches, 21w -1l -1nc
So far Jones by a hair
JJ-22 wins =7 cans,1 middleweight name, 7 names,6 former champs, plus DC
DC-21 wins=10 cans,1 former middleweight champ, 6 names, 3 former champs, 1 hw champ
JJ again
JJ:8 title defenses(4 champs,2 monsters,DC, and Chael)
DC: Two Division Champ(Simultaneous), 3 title defenses(2 monsters and Oez)
I give this one to JJ but can see the argument either way.
JJ

lhw)
5 fights to start(padding)(Brad Bernard, Carlos Eduardo,Anthony Pina, Ryan Verrett,Parker Porter, Moyses Gabin, Andre Gusmao)
Stephen Bonnar(12-4 at time of fight, coming off 2-2 - first big win imo)
Jake O'Brian(Padding),
Matt Hammill-loss for being a cheater,
Brandon Vera(11-4 , had to drop to lhw due to getting beat up at hw, coming off loss to couture- good win)
Vladimir Matyushenko(24-4 , great test for Jones, old veteran- good win)Past Prime?:Yes
Ryan Bader(12-0 -monster- coming off wins over Keith Jardine and lil Nog-great win)Past prime?:No(currently 25-5,Bellator lhw champ)
Mauricio Rua(lhw belt)(19-4, former champ-legend-coming off win over Machida-great win)Past Prime?:Yes(since JJ 6-5 and has dropped L's to most names)
Quintin Jackson(32-8, legend-ufc champ,pride champ-great win)Past Prime?:Yes(since JJ 5-4 with no great wins...maybe Lawal)
Lyoto Machida(17-2, Former Champ-Monster-Enigma- Great win)Past Prime?:No(since JJ 7-5 with some name wins, still KOing fools though)
Rashad Evans(17-1-1, former champ-only loss to Machida)Past Prime?:No(since JJ has gone 2-6, not past prime, just JJ took his soul)
Vitor Belfort(21-9, former champ, legend, coming off win over Anthony Johnson, also...trt)Past Prime?:No(since JJ has gone 5-4-1 with wins over notable names)
Chael Sonnen(28-12-1, middleweight stepping up last minute, Sonnen is a gangster but not a great win for JJ)Past Prime?:no(since JJ has gone 3-2 with name wins)
Alexander Gustafsson(15-1, wins over shogun,Matt Hamill,James Te Huna- great win for Jones)Past Prime?:No
Glover Texeira(22-2, Monster-Chuck lidell protege-Bader,Te Huna,Jackson,etc,-great win)Past Prime?:No
Daniel Cormier(15-0, HW Grand Prix,etc, great win)PP?:No
Ovince St. Preux(19-7,warm up fight-not a great win)PP?:who cares,
Daniel Cormier(No contest due to cheating)
DC

HW)
To start 7 "cans"

Gary Frazier,John Devine,Lucas Browne,Tony Johnson,Jason Riley,Soa Palelei,Devin Cole)(Browne and Johnson were regional champs so technically the best at that level at that time, Palelei is making some noise now but was a noboday then and still not great)
Jeff Monson(42-11, dangerous journeyman-first test-good win)PP?:No(19-14 since DC)
Antonio Silva(16-2-monster-just beat Fedor-great win)PP?:No
Josh Barnett(31-5-former champ-legend-also steroids)PP?:No(since DC 4-2 with name wins)
Dion Staring(Can)
Frank Mir(16-6, former champ-legend) PP?:yes(since DC has gone 2-5)
Roy Nelson(19-8 with some name wins-good win)PP?:does he have a prime?
(Lhw debut)Patrick Cummins(can)
Dan Henderson(30-11, former champ-champ-legend-great win)PP?:Yes
Jon Jones(loss by decision)
Anthony Johnson(19-4 Monster-great win)
Alexander Gustafsson(16-3 perpetual contender-great win)
Anderson Silva(33-7, champ-legend-middleweight- also steroids-great win...kindof)PP?:Yes
Anthony Johnson(22-5, still a monster)
Jon Jones-(no contest because cheating),
Volkan Oezdemir(can(no name wins but decent record))
Stipe Miocic(18-2, HW Champ-Most Defenses-great win)