I have the Marvel ap for Android, I quite like it. The reading portion takes you from panel to panel with each tap, and on larger panels from speech bubble to speech bubble, so it makes it easy to read. They also offer free comics, usually the first of a series, so if you think you may want to read something but aren't sure, you can check out the first issue and see if it catches your interest. Altogether it's a nice app, easy to use and browse.