The race for the lead in U.S. smartphone operating system (OS) consumer market share is tighter than it has ever been. According to November data from The Nielsen Company, the popularity of the Android OS among those who purchased a smartphone in the last six months (40%) makes it the leading OS among recent acquirers.

But despite its surge among recent acquirers, when it comes to overall consumer market share, Android OS (25.8%) is still behind Apple iOS (28.6%). RIM Blackberry’s position is less clear: Its share (26.1%) puts it within the margin of error of both Apple iOS and Android. In other words, RIM remains statistically tied with both Apple for first and Android for third. Apple’s clear lead over Android notwithstanding, this race might still be too close to call.

This much is clear, however: All three smartphone OS leaders – Apple iOS, RIM Blackberry and Android – are benefitting from strong demand for smartphones. In November, 45 percent of recent acquirers chose a smartphone over a feature phone.