Not sure if it's okay to reference my guitar in the marketplace (mods please delete if not), but...
I've got a 512ce from last year in really great condition that's up for sale towards the top of the marketplace section.
I've played the pre-2016 version of the 512ce, but not the 12 fret. The 12-fret version I feel has more bass and "round-ness" to the sound. I liked it a lot better, and enough to buy the 2017 version. Turns out that cedar doesn't really mesh well with my voice, so I'm not playing it much. However, it sounds amazing, and really different from my spruce topped 12-fretter. It's warmer, and mellower. The 12-fret gc body is my favorite as it's insanely comfortable to hold and play, for long periods of time. Personally, I also liked the aesthetic changes they made in the newer versions, with the tortoise binding, instead of the ivoroid. I just think it looks a little nicer with the dark contrast binding. When I bought my 2017, I had considered buying an 2015 at a considerable discount for a NOS guitar, but I much preferred the look of the newer version.