Ditto what TaylorGirl said. The 2015 re-voicing of the 600 and 800 series was a change, not necessarily an improvement, in the opinion of many. V-bracing is the next version of that. The same can be said for 90's era necks versus the NT neck system. My youngest Taylor has a 2010 build date, and I've not missed the subsequent "new and improved" versions. My first Taylor - a 2001 414ce - is chugging along nicely still and is my primary gigging guitar.
If you are old enough to remember the 70's, we faced the same thing with the Chevy Camaro and the Pontiac Trans-Am. They were really the same car, mostly with different trim packages. So a new V-braced 814 or an older X-braced 814 will be slightly different, but far more alike than not. One is likely not dramatically better than the other. YMMV, of course since we all hear differently.
