Apple's iOS might be top smartphone OS in the U.S. in terms of marketshare, but Android is gaining, especially among new smartphone buyers.

The latest smartphone market share survey from Nielsen looks at data from November 2010. This data shows the iPhone has retained pole position in overall smartphone marketshare in the U.S. with an estimated 28.6% of the market. RIM's BlackBerry and Google's Android platforms are essentially tied in second place, with 26.1% and 25.8% respectively.

In fact, Android's numbers are up by almost 6% from another Nielsen survey from the month before. Of course, current market share is only part of the picture. Nielsen's study also tracks smartphone purchases from the last six months, and in this area, Android is the clear winner, representing 40% of purchases.







This kind of momentum has continued to build for Android steadily in the past six months. Looking at the U.S. operating system share in the past six months, Android has continued to grow at rates faster than its competitors. Apple has seen a slight uptick in market share, generally remaining steady, while BlackBerry is losing marketshare against its competitors.







Of course, all three platforms are benefitting from the continued surge in smartphone sales. Nielsen reports that 45% of recent phone buyers choose a smartphone over a feature phone. That underscores just how much room remains in the overall smartphone market.

When it comes time to replace a phone or renew a mobile contract, an increasing number of users are going to be faced with the decision of buying another feature phone or paying the same price (albeit with higher data fees) for a smartphone.

In this area, Android is at a particular advantage, not just because of its strong ties across U.S. carriers but because of the many different models from various manufacturers.