Nielsen and comScore survey US consumers through different methodologies, however they both try to paint a picture of the smartphone patterns of ownership and consumption.
I regularly report on comScore’s data as it’s published on a monthly basis. Nielsen offers updates on a quarterly basis but there is more detail.
The latest report (for Q2) shows smartphone shares by both platform and vendor. The following graph is a treemap built with the Nielsen data:
The same data is also plotted below as a pie chart: