I would upgrade to 2014 if it were me and if we had the hardware for it. I would say that since SQL Server 2008 or maybe 2005 that it is safe to go with the RTM version, or at least once the first hotfix is released (not service pack).
Before considering either 2012 or 2014 I would validate that the application(s) and/or vendor (if vendor supplied) support that version. I have several systems that cannot be upgraded to 2012 yet because the vendor hasn't certified their application yet.
I have several in-house systems that cannot be upgraded until we have time to create a 'test' environment to evaluate all of the code that would need to be changed (if any).
I would never arbitrarily decide to upgrade any instance of SQL Server to a new version until it has been tested and validated on the new version.
Oh yes definitely needs to be tested. I definitely wasn't say to upgrade to 2014 in production without first testing it. What I am saying is that if you are planning on upgrading and can support 2014, then I would go with 2014. We have 5-6 non-prod environments. We would start with dev for the upgrade testing and then work our way through the other environments and then out to prod.
It is not unusual for organisations to maintain the latest version - 1 (i.e 2012). There are a number of benefits: vendor certification, product support, product stability, systems management support. Overall, include in your considerations such factors as : standardisation and easy of management