And Dr X in "Mindcrime II" will be played by...

Yeah it's not the most "live" live album ever recorded. Yeah you are in the minority. :) I still like it a lot.
 
But they're a similar style. I never said they sounded the same, but if you were to put them into a genre it would be the same one.

Just like Slayer and 80s Metallica are thrash bands, but obviously sound very different. Still the same style, though.
 
I've never been a big fan of Priest either. I don't mind Halford's solo stuff (Resurrection, at least, as it's the only one I have) but Priest have never really done it for me.
 
I would consider Priest more the trad metal band, and Maiden more the original power metal band. Priest are more traditional heavy metal, and have fun songs with an underlying heavy metal theme. Maiden have the more serious story telling approach, which makes them quite different. You wouldn't hear Maiden sing a song like Hot Rockin'...likewise Priest wouldn't likely tackle an epic like the Rime. Both are great in a different way.

Maiden have been more consistent throughout their career, and more often have the more consistent albums, but when Priest are at their best they are just as good as Maiden at their best. Again, it is hard, and kind of silly to compare them, because the song writing styles are so completely different.