Android wallet stats
The chart below tries to give an overview of the current (as of Oct. 2014) landscape of Android wallets. The Google Play store does not publicly provide exact download stats for all apps, but rather just the following broad ranges: 50+, 100+, 500+, 1,000+, 5,000+, 10,000+, 50,000 and 250,000+. (Actually, it seems depending on how you access the data, slightly different ranges are used. These are the ones provided by the API I used, whereas the Play Store website uses slightly different ranges, which are a bit more fine grained.) It does provide an exact count of the number of ratings an app has received. Based on these two pieces of data, I have created a somewhat arbitrary "hybrid score", which is calculated as follows: lower_bound_for_number_of_downloads + 25 * number_of_ratings. The general idea behind the hybrid score is, to sort all apps by the download range they fall in (50+, 100+ etc.), but then be able to tell them apart within a range by using the number of ratings as a secondary indicator. Calculating scores in this way results in the chart below:
I have split the chart into three areas, as the top wallet is so far ahead of the bottom wallets, that they would otherwise be hard to see on the chart. A lot of empty space is therefore omitted from the chart. I decided against a logarithmic axis, so that it is still possible to compare growth rates of the different wallets.
Bitcoin Wallet for Android by Andreas Schildbach is leading the field and is far ahead of all the other wallets and in a download range on its own (reported as 250,000+ via the API that I used; the Play Store page reports it as 500,000+). With considerable distance Coinbase and Blockchain follow, which each have 50,000+ downloads (Play Store page reports 100,000+ for both). Another big gap follows, then Mycelium with 10,000+ downloads, then Xapo, KnC, Hive and Green Address with 5,000+ each. Places 9 and 10 are occupied by Paytunia (1,000+ downloads) and Copay (500+ downloads).
For Xapo, Hive and Green Adress one can see jumps in the graph. This is not a sudden rise in popularity, but rather a point in time, where they moved from one download range to another (from 1,000+ to 5,000+) and as result the hybrid score increased sharply.