Alright let me just throw out my input cause......I want to =P
There honestly isn't much a can say that hasn't already been said.
I think debating MC's in general is silly (especially 2 of such high caliber), because in the end there's no definite way to determine who's better.
I suppose I will state my opinion though.
As far as lyrics go I'd say lupe edges Ye out slightly.
With tracks like The "Say Something" freestyle, Twilight Zone, and Carrera Lu, where raw lyrical ability is shown. It's not a complete blowout, however; the edge is apparent.
However artistically I believe Kanye is a good few steps ahead of that man Wasalu. Listening to a Kanye album for the first time just feels like a breathe of fresh air. It also has the Lays effect "You can't just take one". You can't just listen to a few tracks off a Kanye album, once you start listening it pulls you all the way through. His albums mesh better together than any other MC rapping today, and whether that is to be credited to the fact that he makes his own beats, or the fact that he may just be a genius doesn't matter.
That being said you can be the illest rapper in the world, best multis, best metaphors, and best wordlplay, but god damnit if you can't put together a cohesive album, that makes a bond with the listener, to the point where they can't listen to just one track....You'll forever be a step under Ye. And that's not even to say Lupe couldn't, but he hasn't yet. Food and Liquor was amazing (one of my favorite albums), but I don't see it over Late Registration or The College Dropout.
I mean it's cool that "The Cool" was an entire metaphor (literally the whole album was telling a story), but some of the parts were simply boring and didn't make much sense.
So as far as story telling tracks go
Kanye has gems such as: Roses, Blame Game, Spaceships, and Hell of a Life
However Lupe heavily focsues on story telling so again I'd say he edges out Ye here with gems suchs as
The Cool, Kick Push, Kick Push II, He Say She Say, and Hip-Hop Saved My Life.
And as far as Diamonds go Kanye was trying to present a controversial issue to a greater population and thus likely dumbed down his lyrics accordingly, while lupe made Conflict Diamonds before he had any notable recognition and probably could've given a **** about who heard what he was saying at the time. (one song is on a critically acclaimed album, the other on a mixtape).
As far as albums between the two go, I see it as.
Late Registration > The College Dropout/Food and Liquor > My Beautiful Dark Twisted Fantasy > The Cool > Graduation
To be honest I was typing this on and off for about 30 minutes, and I don't even really remember what my points were anymore lol. But I think I hit some of them, but basically just let the albums do the talking. MBDTF vs Lazers? Sure, I'm heavily anticipating Lupe's next piece of work.
As far as this debate goes though? Both artist are amazing, and have their pros and cons, so just listen to who you want.