Here, via ad network Chitika, are the most popular Samsung phones in North America.
The SIII, which is two years old is the most popular. The S4, which came out last year is the second most popular. Interestingly, its phablets aren't all that popular here in the U.S. Only 13% of web traffic from Samsung phones comes from the Galaxy Note I, II, or III.
The lack of phablet traction in the U.S. is interesting. People here were dismissive of phablets when they first hit the market. It looks like they're still not popular here. It seems they're more of a global phenomenon where smartphones are serving as tablets, PCs, and phones, more so than here where those are three different devices.