According to the latest research from Nielsen (http://www.nielsen.com), the high-profile launch of Apple’s iPhone 4S in the fall had an enormous impact on the proportion of smartphone owners who chose an iPhone.

Among recent acquirers, meaning those who said they got a new device within the past three months, 44.5% of those surveyed in December said they chose an iPhone, compared to just 25.1% in October, according to the research group. What's more, 57% of new iPhone owners surveyed in December said they got an iPhone 4S.

Android continues to hold the lead among all smartphone users, with 46.3% of all smartphone owners surveyed in the fourth quarter of 2011 (Q42011) reporting they have an Android-based mobile phone. As of Q42011, 46% of US mobile consumers had smartphones, and that figure is growing quickly. In fact, 60% of those who said they got a new device within the last three months chose a smartphone over a feature phone.