A particularly snazzy feature, Office On Demand can "stream" a copy of Office 365 Home Premium to a PC for provisional use. Once you're finished, you simply close the program; it uninstalls itself without a trace. I used Office on Demand to run Word 2013 on a Dell Latitude 6430u Ultrabook, and while the program sometimes stalled to download additional pieces as needed, I was able to get completely up and running in about five minutes. The installers are cached locally, so even after a reboot I was able to fire up fresh instances of Word from Office On Demand in seconds. It doesn't remember any user settings, but that makes sense if you're trying not to leave anything behind. (A consequent downside: Custom dictionaries aren't streamed to Office On Demand setups.)
Meaningful improvementsThe biggest visible change to each app is the Modern UI-style theme, plus a setting to make visual elements more useful on a touch display by ramping up their size. Outlook contrasts most dramatically with its previous versions, and it looks far less crowded and busy. But the changes to Outlook don't stop there: It has a more efficient mail-storage format; lets you reply to emails "inline," meaning directly from the inbox (a nice way to avoid cluttering your screen with open windows); and finally lets you view appointments or contact information without having to switch away from email.
Outlook's cleaned up Modern UI makes dealing with piles of mail (and contacts, and events) far less suffocating.
I mentioned collaborative editing -- Word makes good use of it -- but a few other new features in Word turned my head even more. In-document comments now work more like discussion threads, so you can pass detailed notes about changes back and forth without crowding the document. Markup can also be presented in an abbreviated form, and comments can be marked as "done" when you've responded to them. Another nice touch is the "pick up where you left off" function. When you reopen a previously edited document in Word, the program remembers the last edit point and offers to take you there.
One of Word's best new features is remembering what you were doing. When you return to a document, you're invited to pick up right where you left off when editing.