I upgrade frequently for a few reasons: being a tech junkie, working in the industry, and having (legal) access to software via Dreamspark and TechNet. Having said that, I understand not wanting to shell out large amounts of money for upgrades, especially ones you may not need. But once the product is no longer being supported, at that point, I think it's time to upgrade or switch.Yes, but it's also quite costly. If you own a previous version, 2003/2007/2010...it would seem hard to pony up the money again for the upgrade.
Download: Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint File Formats - Microsoft Download Center - Download Details
So I ask again, what are the VALID concerns about the docx format?
There is one compelling reason not to install Office 2003 on Windows 8 RTM: it breaks Windows 8 Update. See this post:
Office 2003 + Windows 8 Pro x64
As an addendum to that information, I have just confirmed that the Microsoft's Metro Apps will not be listed or updated automatically after the partial (compromise) fix for Office 2003 is applied, namely switching off the check for other installed Microsoft applications. However, it is possible to run a manual update of the Metro apps:
How to update Windows 8 Apps
And the procedure above does work.
Docx. file format is there because of advanced formatting in Office 2010 and 2013 that 2003 doesn't understand correctly. I've seen issues when converting a docx. file into Word 2003, but not when it's done in Word 2010.
My concern is that most schools/colleges today still require students to submit their assignment in .doc format instead of .docx.
Davidvoyage: Truly no need for concern — not only can Word 2007 and later 'Save As' to doc format, but this old Word format can also be made the default and docx then becomes a 'Save As' option.
Your original post suggests that you have Office 2010. If so, install it in Windows 8 and enjoy. For many versions now, going back to Office 2000 I think, the Office upgrade option to remove a prior version has worked extremely well. (Of course, the transition from 2003 to 2007 was a nightmare because of the then new RIBBON and the introduction of docx, so that many individual settings, macros, templates, etc. required much careful attention and tweaking.) But the transition from 2010 to 2013 should be comparatively straightforward, so that if it turns out 2013 offers compelling grounds for you to upgrade, you will be able to do so confident of not screwing up you Windows 8 system.
I have successfully installed the Office 2013 customer preview on my Windows 8 test PC, and it is much like 2010 (I normally use Windows XP and Office 2003, so Windows 8 and Office 2013 would be quite a jump, if I decide to go that way when they are properly released). In fact, one improvement over Word 2010 which Word 2013 does not have, which annoys me, is proper small caps support. Quite a few OpenType fonts also contain proper small caps, with the same weight as the regular characters, but Word 2013 - like its predecessor - does not use them; it shrinks the caps instead, which looks sloppy. Publisher, on the other hand, does support true small caps - as does Publisher 2010. So why not Word 2013? Sloppy, Microsoft, sloppy!