Over the past 2 years or so, Android has managed to maintain its market share in US at around 50% or so. It has gone down as low as 45% in some seasons, or as high as 55% in others, but overall it has remained around 50-52%, with Apple at around 40 percent (although this level is a little more recent for Apple, since the downfall of Blackberry, which helped them jump from a little over 30 percent to 40 percent).
A new report for the month of October confirms this, and puts the combined market share of Android OEM's in US at 52 percent, while Apple managed to hold at 40.6 percent. This makes Apple the biggest smartphone OEM in US, but that's always been the case, considering how popular Apple has always been in US since the iPod days over the past decade, and how strong the Apple culture is in US. Apple will continue to do well in US, and will continue to have the mindshare, even as Android has the biggest market share.
Samsung grew 1.3% reaching 25.4% market share in US, Motorola grew 0.1% to 7%, HTC dropped 1.3% to 6.7% (same different as Samsung grew, which is perhaps not a coincidence), and LG also dropped 0.2% to 6.6%. Overall, there's not much change in the market, but we should begin to see bigger changes next year, as I expect more growth from Motorola, especially with its inexpensive Moto G smartphone.
Worldwide, things are a little different, with Android being at around 80 percent market share right now, and Apple around 12 percent. that's a much bigger difference, and Apple doesn't have the same influence it has on US consumers either. Things should get worse for Apple as time passes by (at least compared to Android, not necessarily financially), because that gap in market share will pose a bigger problem in the future, when we're talking about several billion smartphone users, and when Android will get an app store that matches its market share a lot more (expect a lot more apps in the Play Store than the app store in the future).