Hi. I mentioned a few times recently on here (I don't remember the post numbers) how I settled on my 816ce last summer. After a long and fun-filled search, it boiled down to two Taylors - the 614 versus the 816. They're very similarly priced and for me personally there was nothing to split the GS versus GA in terms of playability. Tonally, though, there is a big difference between the two. I thought the 600 was a little too bright up top, and dropped away a little in the mid-range (I'm splitting hairs a little here - the tone is still exceptional), whereas the 800 was noticeably more balanced, but with a much richer bass. The 800 was noticeably louder, meaning you don't have to hit it so hard to get a big noise, but in my case that may have been a GS/GA thing. Also, although I loved the look of the maple and the torrefied top, I thought the aesthetic was let down a little by the inlay design and other little details. Overall the 800 has a higher specification in detail finishing which is quite obvious when you hold the two side by side, and at that price, the way it looks is just as important as the way it sounds.
As ever, my advice is to try to A/B compare the two before you make a decision, but either way you'll be choosing a special guitar. Good luck...