Both fighters were brought along in almost identical fashion although Bruno failed everytime he stepped up before finally winning a version of the title after his fourth attempt. Poll time.
McCall had beaten Lewis - who was WBC Champion and #3 ranked heavyweight at the time - and Holmes - who was #7 ranked heavyweight - in the two fights prior to meeting Bruno. This had led him to being ranked as one of the two best fighters in the heavyweight division. Stiverne - having been robbed of his shot at Vitali - had beaten Areola a second time to confirm his right to pick up the then vacant WBC Title. Areola was #7 ranked heavyweight when Stiverne beat him and this left him as 3rd in the heavyweight rankings behind Wlad and Povetkin. McCall was the better scalp.
clearly McCall is the better win Stiverne's best win before losing to Wilder was US level Arreola and a shot Ray Austin, both of whom were winning the fights before Stiverne's power saved him McCall had knocked out future HW king LL, beaten a worn out Larry Holmes, and went on to knockout future titlist Maskaev in his next fight
Bruno by far and away, it's not even competitive. Bruno beat McCall who beat undefeated Lennox Lewis for the WBC title. Wilder beat Stiverne who beat Arreola for the vacant title.