The results are clear: OfficeSuite 8 Premium is by far the best overall office suite on Android today. From its excellent UI to its commendable feature set, the app is in a league of its own. At $19.99, the full version isn't cheap, but you get what you pay for, which is the best mobile office experience with next to no compromises. The less fully featured OfficeSuite 8 Pro ($9.99) is a worthy one-step-down alternative, as is the basic, ad-supported free version of the main OfficeSuite app.
Microsoft's new Office apps could be a close second, but the requirement of an ongoing monthly subscription for a complete set of features is difficult to justify -- especially when that set of features is less robust than what you'd get with a one-time purchase of OfficeSuite. The fact that the proper Word, Excel, and PowerPoint apps won't work on Android smartphones -- leaving you with only the shamefully subpar Office Mobile substitute -- is indefensible and takes a serious toll on Microsoft's scores.
If basic on-the-go word processing is all you require -- and you work primarily with Google services -- Google's free Google Docs may be good enough. The spreadsheet and presentation editors are far less functional, but depending on your needs, they might suffice.
Polaris Office is adequate but unremarkable. The basic program is free, so if you want more functionality than Google's suite but don't want to pay for OfficeSuite -- or use OfficeSuite's lower-priced or free offerings -- it could be worth considering. But you'll get a significantly less powerful program and less pleasant overall user experience than what OfficeSuite provides.
WPS Mobile Office is a small but significant step behind, while Docs to Go is far too flawed to be taken seriously as a viable option.
With that, you're officially armed with all the necessary knowledge to make your decision. Grab the mobile office suite that best suits your needs -- and be productive wherever you may go.