It's a matter of taste. Bruce is more of a traditional metal singer, where Paul brought an unique raw, aggressive vibe to Maiden. I always preferred that. The only Maiden album with Bruce I really liked was NOTB. Here's a song recorded with both of them.
Musick has Charms to sooth a savage Breast, To soften Rocks, or bend a knotted Oak. I've read, that things inanimate have mov'd, And, as with living Souls, have been inform'd, By Magick Numbers and persuasive Sound. What then am I? Am I more senseless grown Than Trees, or Flint? O force of constant Woe! 'Tis not in Harmony to calm my Griefs. Anselmo sleeps, and is at Peace; last Night The silent Tomb receiv'd the good Old King; He and his Sorrows now are safely lodg'd Within its cold, but hospitable Bosom. Why am not I at Peace?