(Edit: this is data for just this season) Here is a data driven comparison of the 2...
Advanced metrics (ShotQuality, Torvik, Evan Miya & KenPom)
ShotQuality Points Per Possession (expected points per shot)
Clingan: 1.22 (88th percentile)
Johnson: 1.49 (99th percentile)
Torvik Box Score +/-
Clingan: +7.8
Johnson: +5.6
Evan Miya Bayesian Performance Rating (a metric that looks at offensive and defensive value to the team)
Clingan: 9.23 (2nd nationally among qualifying D1 players)
Johnson: 0.62 (1356th nationally among qualifying D1 players)
KenPom Offensive Rating
Clingan: 121.8 (28.1% usage) (398th nationally among qualifying D1 players)
Johnson: 126.2 (16.4% usage) (286th nationally among qualifying D1 players)
Other stats (from CBBanalytics.com)
Points / 40 min
Clingan: 24.4 (95th percentile)
Johnson 17.6 (76th percentile)
Offensive Rebounding %
Clingan: 21.5% (98th percentile)
Johnson: 10.6% (73rd percentile)
Hakeem Percent (% of blocks + steals on defensive possessions)
Clingan: 12.8% (95th percentile)
Johnson: 8.6% (84th percentile)
Personal Foul Efficiency (ratio of steals + blocks to fouls)
Clingan: 1.56X (94th percentile)
Johnson: 0.82X (76th percentile)
Clingan is clearly better (especially when defense is factored in) but Johnson has been very good this year, too.