CloudOn does the seemingly impossible. It hosts Microsoft Office in the cloud, then makes it available on your iPhone, iPad, or Android tablet. PC World's Yardena Arar called it her"favorite cloud-hosted virtual Office service."

With version 4.0, CloudOn is now available for Android smartphones as well. And it brings some much-needed new features to the table, while retaining (for the moment, anyway) the best possible price: It's free.

If you've used the app in the past (on another device), you'll be glad to know that version 4.0 supports both portrait and landscape views, the latter a very welcome (and overdue) addition.

Also new: CloudOn FileSpace, a place to add notes and view all activity on a single file, including edits, for real-time updates on documents. As always, you can share and view Office documents directly from email, Box, Dropbox, Google Drive, and SkyDrive.

If you've used the app in the past (on another device), you'll be glad to know that version 4.0 supports both portrait and landscape views, the latter a very welcome (and overdue) addition.

Also new: CloudOn FileSpace, a place to add notes and view all activity on a single file, including edits, for real-time updates on documents. As always, you can share and view Office documents directly from email, Box, Dropbox, Google Drive, and SkyDrive

If you've used the app in the past (on another device), you'll be glad to know that version 4.0 supports both portrait and landscape views, the latter a very welcome (and overdue) addition.

Also new: CloudOn FileSpace, a place to add notes and view all activity on a single file, including edits, for real-time updates on documents. As always, you can share and view Office documents directly from email, Box, Dropbox, Google Drive, and SkyDrive.

CloudOn 4.0 can run on Android phones including the Samsung Galaxy S3, Galaxy Nexus and Nexus 4G, Galaxy Note and Note II, and Galaxy S II Skyrocket. According to a CloudOn rep, these are among the devices the company has "spent the most time on developing and testing." Other phones may work as well (check the Google Play Store), but "it shouldn't be too long before most Android phones are perfectly CloudOn compatible."

I tested the app and service on a Galaxy S3 and found that it worked as advertised. With just a few taps I was able to access my Dropbox account, open an Excel spreadsheet, and edit it.

That said, let's not fool ourselves into thinking Microsoft Office works well within the tiny confines of a smartphone—even one as large as, say, the Galaxy Note II. Although you can create documents via CloudOn, it's just not practical to do so on a phone.

Instead, keep this on hand for those times when you need to review or make a few small changes to a document. For instances like those, CloudOn is hard to beat—especially given that it lets you work within such a familiar interface.