When you open up any type of document, you'll see tools across the top of the screen. In Word you can swipe to read through the document, or use the buttons at the top to share; open a text-formatting screen for highlighting and other format options; or go to a Viewing options screen for looking at Outline Views or for performing a search. Editing in Word is as easy as tapping on the screen and typing. There are formatting options to bold, underline, or italicize text, and you can select from three different colors for text or when you want to highlight words or sentences in a doc. You can also make comments on shared Word documents. When you're finished, just save to SkyDrive, and your document will have your changes and be available to edit from your other devices.
In Excel you can view and edit your data with tools at the top, and switch to other spreadsheets and charts associated with a project using the tabs at the bottom. Just like on a desktop, you can enter formulas for cells, and -- when you edit a cell -- the values will automatically update in your spreadsheet. You also can quickly create a chart of selected data by highlighting fields, opening the editing tools, and touching Create Chart. You have six different chart types to choose from, and the app will automatically create the chart in a new tab.
With PowerPoint, you can't create a new presentation like you can for Word and Excel. Still you can view previously made presentations, make small edits, move slides around, and view and edit speaker notes so you can practice a presentation on the go. The app has a button at the top to let you quickly navigate to other slides, or you can swipe horizontally to navigate to the previous or next slide. To get a feel for your presentation, you also can switch to landscape mode then swipe to view your slides in full screen. You won't be able to create new slides or perform more-complex actions like adding transitions, but the app will still be useful for smaller edits before a big meeting.
So what's the problem?
Granted, I have only a couple of issues with Office Mobile, but they are big ones. The app is definitely useful for subscribers (and if you have an Office 365 subscription, why not download it?), but if you can access watered-down versions of Office for free online, it seems reasonable that you'd be able to do the same with this app with limited editing features. It would be better if the current version of the app were free and tied to the Web apps, but a more robust version with more features were tied to the Office 365 subscription. As is, it's giving you much less than what you get for free in a Web browser, but you still have to subscribe to the service to use it. Fortunately, if you just want to check out the app, you can sign up for a free trial of Office 365 at Office.com. Once signed up, the Office Mobile app will work until the end of your trial period.
The other problem is that Office Mobile is optimized only for iPhone, meaning that you'll have to use pixel-doubling on the iPad if you want to run it full screen. With so many iPads in the wild and the better screen real estate on the larger Apple device, it seems like a perfect fit for those who want to edit documents from the couch. Hopefully a future update will address this issue, but for now iPad users are mostly out of luck.
Hopefully this is just the first round and Microsoft will either add to Office Mobile or separate it into different downloadable versions. While Office Mobile doesn't give you a lot of features, it's definitely useful to subscribers for making quick edits on the go. But I think Microsoft could have captured a lot more hearts by making this app free to use without a subscription, and providing a more robust version for subscribers. Making it available to iPad users would be even better.