Its not about who is bigger, as how is bigger defined.?
its about who is better, more influencial, and subjectively makes better music.
to me the nod again goes to JUDAS, as without Judas taking Maiden out on the killers tour, who knows if Maiden would have been so accepted, remember that JUDAS took Maiden out on a few tours, it got the point that we only thought of them as "Judas's opener" remember there were lots of rock/quasi metal bands( Saxon) that would have sold their soul for that opening gig...most metal bands failed, Maiden was not nearly as mind blowing back then..Paul I thought was a more interesting front man..his voice seemed to allow the band to show through better, Bruce to me was them trying to get their own Halford..
Plus: Rob was larger then life.. he was magic, his presence was unreal.. his voice was mind numbing. I remember being at the Paladium in NYC( 1980?) and when he brought the bike out we thought the building was going to cave in, he OWNED.
Bruce just ran around howling in comparison..