Microsoft Office 2013 and Office 365 are now available for purchase in retail stores in 162 different countries as well as online at Office.com. Redmond is making a bold decision by moving to a subscription model with Office 365 but with such a heavy focus on cloud computing as of late, Microsoft clearly feels that now is as good a time as any to further explore the emerging market.

Those electing to use the subscription model will pay $99.99 per year for access to Word, Excel, PowerPoint, OneNote, Outlook, Publisher and Access. This bundle allows the user to install the software on five different systems - Mac and PC are both supported – and there’s even a web portal that allows you to work from a computer that doesn’t have the software installed.

The subscription also includes 20GB of SkyDrive storage and 60 minutes of Skype calls per month. The same deal can be had for $9.99 per month if the idea of an annual subscription doesn’t appeal to you.

There’s also the traditional one-time purchase version for $139.99 known as Office Home and Student 2013. This watered down version includes Word, Excel, PowerPoint and OneNote and can only be installed on a single computer. SkyDrive access isn’t included either so you’ll have to resort to tried and true tactics if you want to take your files with you.

Another big difference between this release and previous Office products is that retail versions in large markets like the US and the UK won’t include a physical DVD. Instead, Microsoft is simply putting product codes inside familiar retail boxes that require users to go online and download / activate the software.

At the end of the day, you’ll likely want to ask yourself a number of questions before deciding on which route is best for you. How many computers do you plan to install Office on? Which components are you likely to use? Does SkyDrive access appeal to you? How do you feel about paying $100 each year for the foreseeable future?