Well, I finished converting Doodle Rocket Ship in a couple of days, and I've now submitted it to both Google Play and the Amazon store.  I did a bit of optimising for 7inch screen size before submitting to Amazon.

I submitted to Google Play yesterday, and one immediate difference to the App Store is apparent - any app you submit will get at least a few hundred downloads if it's free on the AppStore, due to it's 'what's new' section.  There is no equivalent on Play, and therefore no free publicity or early download boost. This will be an interesting experiment!