I went through the whole Maiden discography over the weekend and will probably do some sort of write up on overall thoughts (maybe in the Maiden thread) but regarding The X Factor I think it's actually a pretty cool and unique album on its own but it doesn't really quite sound like an Iron Maiden album. It's not one of my favorites but I would say it gets more hate than it deserves. While the Blaze era will be remembered as the weakest Maiden era I think there are some redeeming factors. Virtual XI definitely sounds more like Iron Maiden (but with a weaker singer) but I think The X Factor stands out with a different mood/atmosphere.
Would be curious to read it. My favorites are piece of mind, number of the beast, powerslave, somewhere in time and iron maiden. I think those tend to be their most popular though