Other than games, when I see apps available on both and that were ported from the iOS version it is very apparent they are not "proper" Android apps. Big clues are having menu and back buttons. Others are using builtin 3rd party integration (eg fb, twitter, dropbox) instead of the system.
A well structured Android application is like a mashup of different screens, processing (services), event handlers (broadcast receivers), data (content providers), user accounts etc. And it works with other components on the system, not its own little island as on iOS.
You haven't stated what your app is so this issue may not apply. A good example of a bad app is "Beat The Traffic" which is terrible on Android being an iOS port.