usability - Should I follow the Android guideline or keep my app's own style when porting it from iOS?

My new project is to port an iOS app to Android platform. Before get started, I'm quite confused on whether I should follow google's guideline since some big titles on Android platform still keep the same look as iOS version. Style here means the entire design of the app, such as app navigation, theme, and layout.

Please help if you have any suggestions!