More bad than goods, and some of it subjective, I dislike the default reading view for Word. In Office 2010, there was an automatic message, something along the lines of "preview only - click to edit." ( A simple click and either you're viewing or your editing. Now, you open and then have to select from the menu to open it to edit.

Excel - I LIKE the Powerview options and some other data enhances but WAY TOO unstable. Just working with a couple of spreadsheets in normal operations and it crashed several times. The problem with running apps in Excel running in-memory (Powerview) tends to make it way too unstable.

I am running Office 2010 and Office 2013. They do NOT play well together. My default - go to choice is Outlook 2010, but if I need to mail out a document from Excel or Word 2013, no go. They only see Outlook 2013, so I have to go into Outlook and attach the files. And running two copies of Excel - Explorer defaults automatically to Outlook 2013. Files that are pinned to my taskbar can't be opened by Excel 2010, but open fine in Excel 2013 - even after I pointed the link to Office/Excel 2010.

I realize I am only using the initial preview release and I look forward to the official release, but the programs need to "play nice" and get a whole lot more stable before I commit to 2013.