I'm not counting both of their slow starts to their careers, but they are both very streaky.
2015 (since FT for JBJ) to today
Monthly
Bogey
2015: >>>.761/.876 (Pretty consistent)
2016: .785/.1.017/.815/.830/.599/.750 (A little more inconsistent: 1 very big, 2 pretty good, 2 in the middle, 1 very bad)
2017: .731/.949/.763/.452/.683/.792 (Yo-yo: 1 very good, 3 middle, 1 pretty bad and 1 horrible)
JBJ
2015: 1.163/.739 (1 great- 1 middle, I guess you could say inconsistent, but it's only 2 months and none were very bad))
2016: .807/1.175/.805/.839/.651/.731 (4 months over .800 with one being great, 1 okay, 1 bad, but nothing below .651)
2017: .596/.808/.1.009/.596/.770/.529 (1 great, 2 good, 3 very bad-- very streaky year.)
Not counting September 2017:
.452 Bogey
.596 JBJ
.596 JBJ
.599 Bogey
.651 JBJ
.683 Bogey
.731 Bogey
.731 JBJ
.739 JBJ
.750 Bogey (mean)
.761 Bogey
.763 Bogey
.770 JBJ
.785 Bogey
.805 JBJ
.807 JBJ
.808 JBJ
.815 Bogey
.830 Bogey
.839 JBJ
.876 Bogey
.949 Bogey
1.009 JBJ
1.017 Bogey
1.163 JBJ
1.175 JBJ
To me, they look pretty even. If September continues with JBJ slumping badly, they will both have about the same amount of bad months with JBJ having more great months.
Bogey has a cluster in the .700's while JBj has one in the low .800's.
They are 3-3 in the bottom 6 monthly OPS.
They are 3-3 in the top 6 OPS.