let's break it down a bit:
best frontman - this is damned close, as Bruce is amazing, but let's face it: Rob is the living, breathing embodiment of all that is metal. He OWNS a stage as no others before or since. Although Bruce is a gift to the metal world, Rob dominates it.
best guitar team: again, it's nearly impossible to choose, but this time, the nod goes to Maiden, and that's due mainly to Adrian Smith. SImply stated, I think his sense of melody is superb and elevates him to a superior level.
most classic albums: Priest has released records since '74, Maiden since '80, so Priest has a larger catalog to choose from.
IMO, JP's absolute classics are: Sad Wings, Stained Class, Killing Machine, Unleashed, British Steele, Screaming, Defenders & Painkiller. That's 8.
IMO, Maiden's absolute classics are: the first 8 (debut thru 7th Son including LAD). That's 8, also. Edge: tie
best recent material: Without question, Maiden. DOD and BNW are friggin great records, and with time, will probably achieve classic status. AOR was mediocre, at best. Edge: Maiden
damn, this is hard.......if I was forced to choose, I'd give the slightest edge to Maiden. But then there are times when I'm in a "Priest kick" and consider them the single greatest band ever......this is impossible!