First, a subscription to CC doesn't void your perpetual license for CS6, and you can leave it installed.
Second, if your work is for print, in my opinion you'll find little new of value to you other than support for the Retina display, but download the trial and see for yourself.
On the other hand, of your work might expand into digital publishing, or you'd like to explore the new features like Fixed Layout EPUB, InDesign CC 2014 is definitely the way to go. But you can still keep your copy of CS6 there for when you need it. You might be pleasantly surprised by some of the changes (color groups, for example). You settings should be migrated from CS6. Read about that here:
In fact, the original CC version (InDesign 9) now the CC 2014 (InDesign 10) releases have one important improvement that trumps almost all the other new and improved features combined, especially if you have long, complex documents.
InDesign is now a 64-bit application for both MacOS and Windows. (32-bit versions are still available for those with old OS versions or incompatible plug-ins!) The 64-bit aspect allows opening, editing, printing, and PDF-exporting of long and/or very graphically-complex InDesign documents without the problems associated with running out of address space, problems that were quite common with InDesign 8 (CS6) and earlier although most users experiencing such problems didn't usually recognize the problem as that of running out of address space (not physical memory).
I disagree, I see a lot of additional value in CC2014 over CS6 when it comes to the new footnote behavior (text wrapping), organizing colors in the same way as styles, improved tables.
Don’t forget the increased numbers of dictionaries included (ok, you could add languages since CS6).
Since the cloud you can also add languages of other versions as this will add functionality and menu items for ME or Asian languages in your primary version too. E.g. I have sometimes to print material with Hebrew or Arabic parts. (I don’t understand these idiomas, but I get text delivered from native speakers.) In the past I had to pay for specific plugins, to get this work, now I can do it without additional cost.
And there is a lot more of additional functionality with CC2014 I would really miss. But the new path with Illustrator and InDesign is now more improving the quality easier work less the flashy effects which are easy for the marketing team to talk about but often useless for power users.