Which last are they on?
fair warning - once you find out, you're going to start your collection all over again. I'll leave the pros here to answer.
You're using three terms to talk about the same thing. Shell Cordovan, Shell or Cordovan are all the same thing. Horween is (one of?)the branded shell used by AE.
Some of AE's shoes already come in shell. The MTO shell are for folks that want special order shoes made in shell in the color and design that they like. If you ever get the chance to go to an AE store, ask them if they have any shell on display. You'll be able to see, feel and smell the difference.
I was hoping this wouldnt be the case, but sadly I can confirm this as truth...I just received and wore my first pair of cordovan shoes about a week ago...I was truly hoping this was a myth, but alas, I see exactly what people are speaking of regarding this phenomenon. It truly sucks, but even my very uninspiring brown cordovan Dundees, have got me SERIOUSLY contemplating only ordering cordovan going forward...Im actually not blown away by the color at all...Its a rather mundane brown that, so far, has little personality..but that gloss is just beautiful, and I cant even say Im entirely satisfied with my purchase. And I cant pinpoint what it is that makes it seem more appealing than calf (maybe its just the pricetag alone) but damn that gloss more than makes up for any disappointment Ive harbored.
Some shell shoes:
Black, new Burgundy, old Burgundy, Brown, Brown, Cappuccino, Walnut
I've actually got two more on the way, a cappuccino/walnut Shelton and a walnut MacNeil. They're addicting!