I just posted a lovely long piece on the Tin Man Games blog about our thoughts on Android, WP7 and Kindle, you should totally go and check it out:

and now a word about platforms

The Android marketplace (and the other Android compatible app stores) are all a bit different, and you are not required to have an account at the store to use your Android phone. This is a boon for some people who don’t ever need to buy stuff, or don’t want their credit card details on file somewhere, but it is a bane for the casual games on those devices. Adding that extra hurdle just to spend a few bucks on an app seems to take it’s toll in purchase numbers.

Cheers!
-B