Among midrange to high end Windows phones, there are two main SOCs.
The Icon (Verizon only), Samsung ATIV SE (Verizon only), 1520 (AT&T only), 930 (international only; possibly coming to the US in a few months due to retarded carrier politics) have the Snapdragon 800. These are all basically the same phone except the 1520 has the huge 6" screen and an SD card slot.
The 810, 820, 822, 920, 925, 928, and 1020 all use the Snapdragon S4, which is a little out of date. It was the bread and butter of high end smartphones in 2012, shipping in the US versions of the HTC One S and One X and Samsung Galaxy S3, and it's still serviceable today (I have a Lumia 810 and love it), but it's not getting any newer.
There's also the Lumia 520/521, and the upcoming 630/635, but these are low end devices that probably don't interest you.
Essentially, if you want a high end Windows phone, Verizon is the best carrier because you have your choice of a Nokia and a Samsung using the best hardware available on the platform. The only other choice is AT&T and you'd have to use the 1520 phablet, which some people think is too big.