Next page: Spreadsheets, email, calendars, and costs...
Google's spreadsheet app supports basic Excel functionality--multiple sheets in a workspace, cross-sheet references, and standard formulas. It also has formatting options, charts, drawings, images, gadgets and scripts. Yet, when saving a Google spreadsheet in Excel format, the charts may look a little different, and some functionality might be lost. The same is true when converting an Excel document to edit in Google Apps.
The Excel Web App does have autosave, background colors on cells work fine, and multiple people can edit online at once. It supports many more features than Google's spreadsheets do. Cell formats, charts, formulas, and many other advanced functions work perfectly. Not everything is supported, such as objects or tables that pull in data from outside sources. However, if you upload files saved in older Excel formats, such as .xls, you will need to re-save them first in the latest .xlsx format to edit them.
Winner: Microsoft's Excel Web App is superior to Google Spreadsheets.
Email and calendars
Microsoft's Outlook, Calendar, Contacts, and Tasks are similar to Google's counterparts. Outlook allows emails to be grouped into folders and subfolders, while Google has labels and sublabels. A Google email can have multiple labels, but an Outlook email can be copied to multiple folders, and a "Category" option is similar to Gmail's labels. So it's pretty much a wash.
Gmail integrates well with many of Google's other tools. Get a foreign-language email? Gmail offers to translate it. Text chat with your contacts without leaving Gmail, add them to your Google+ circles, start a voice or video call, or set up a hangout video conference with several people.
Both Outlook and Gmail have nice text editors. The Outlook Web App opens a new pop-up window when a user is reading or creating email--an annoying habit since I have pop-ups blocked.
If you've used the free Outlook that comes with Microsoft's personal SkyDrive service, you'll find quite a few differences. The SkyDrive version has some nice tools not in the Office 365 version of Outlook. For example, the folder navigation sidebar on the left includes "Quick views" to quickly scan through emails with attached documents, photos, or shipping updates.