There has long been an assumption that Android users are, on average, younger than iOS users. Maybe not.
From ReadWriteWeb- "Surprisingly, there is little hard demographic data available to the public on iPhone/iPad buyers. Research firm Gartner (which tracks worldwide smartphone shipments by vendor) does not know who is buying these devices. Apple and the mobile carriers like AT&T and Verizon are certainly not giving out demographic information. The best sources are advertisers and marketers. Essentially, any company that specializes in behavioral and demographic targeting.
In that vein, the best targeting information comes from companies like comScore that focus on surveys and tracking on behalf of advertisers and publishers. In comScore’s latest data (from Aug. 2012), 47.2% of iPhone users are aged 35 years or older. So those under 35 years old actually make up the majority of iPhone users. For tablets, the iPad skews a little older with 55% of users 35 years old or older..."