We decided to split into two email addresses instead of one because of the likelihood of users modifying the Subject line or Body in a way where it wouldn't be evident which platform they're using. It also keeps the backing mechanism, Google Groups, cleaner for the users who have read access to it.
An additional suggestion was to break things up into more email addresses to accommodate for the other apps, possibly using aliases to divert the messages to the existing two groups. For example:
Yuvi suggested we ought to bring this discussion onto mobile-l. Any feedback on going from two to four email addresses (and possibly more depending if more apps are created for these platforms)?