I for one chose Iron Maiden
Judas Priest...well I don't know, I'd never say they're bad or something. I just can say I listened to a few songs and it didn't touch me at all, didn't give me a feeling or something.
When I first listened to Iron Maiden - not knowing what it was - I felt obsessed from the beginning and curious of the rest of their music but that wasn't the case in Judas Priest, I don't know why.
I just know what I like in Iron Maiden's music. And this is for example the way how some lyrics fit the music or the other way round. For example in Hallowed be thy name...the beginning gives you a feeling of the situation and you can imagine the whole story before your eyes. Anyway I like the stories and the lyrics in Maiden's songs.
Another thing I appreciate is the use of Hi-Hat and the drums anyway. The rhythms don't seem boring to me. I'm not a drum player but the Iron Maiden drums seem quite interesting to me although I understand almost nothing of drums.
Moreover playing Iron Maiden on guitar or bass simply kicks ass.
For the vocals...I like Bruce Dickinson's voice a lot, especially on the later albums, but I also liked Blaze Bayley, even if most people don't...so well, Maiden was one of my first metal bands and convinced me of this style of music. So, yeah, my vote goes to them.
greets