Like a unicorn trotting out of the wilderness on a rainbow, Microsoft Office has finally arrived on the iPhone after years of fevered rumors that bordered on myth. Starting today, workaholics can poke around on their phone's tiny screen to edit Word, Excel, and PowerPoint documents.

The catch is you'll need to subscribe to Office 365 and save your work in SkyDrive, which means you'll have to pony up, oh, $100 a year.

So is Office Mobile worth it?

Microsoft "isn't quite re-inventing the wheel here," says Pete Pachal at Mashable. "Microsoft has done a good job of creating 'mini' versions of these three apps for the iPhone's screen," but the tiny interface runs into the same limitations plaguing Office Mobile for Windows Phone. "Copying and pasting isn't as straightforward as it should be. And you can't edit some types of documents."

You're also limited to certain documents. "You can freely create Word and Excel documents, but there are no options to create a PowerPoint presentation from the device," says Tom Warren at The Verge. Also, the editing interface isn't "as straightforward as it should be."

Initially I was confused. I tried to highlight text using the familiar controls of iOS, but I was greeted with a comment notice. Eventually I discovered that you have to double tap on words to get the typical highlight controls. Once you've highlighted text it's easy to hit the edit button and gain access to formatting options. [The Verge]

It should also be noted that Office Mobile isn't available for the iPad, but that's likely by design. "Microsoft can't kill the only legitimate selling point of its struggling Surface tablet," says Matt Burns at TechCrunch.

Then there's the elephant in the room: Google Docs, which has an attractive selling point of being absolutely free on iOS devices. That's hard to compete with if you're Microsoft.

But if you do 98 percent of your work in Word or Excel, and your employer isn't shy about opening up its wallet, Office Mobile might be worth pestering your boss about. Give it a try here.