Like their iPhone counterparts, the Android apps require an Office 365 subscription (they're free for those who have one). There's still no tablet support - Microsoft continues to promote the Office Web Apps for tablets.
Reviews for the iPhone apps (I, II, III) were muted. The apps receive praise for their minimalist design and offline/SkyDrive support, but are criticized for failing to work well with 3rd-party apps, and for missing desired formatting/editing features.
Microsoft is promising it will do a better job of supporting iOS/Android. Hardware chief Julie Larson-Green: "We can provide unique, differentiated experiences on our devices and on other people’s devices."
The Android app launch comes as ex-Facebook CTO Bret Taylor unveils Quip, a mobile-optimized word processor that (like Google Apps) emphasizes collaborative editing and is receiving positive early buzz.