I seem to be in the minority here, but I've never had any major issues (knock on wood) with either version. Sync works perfectly every time. 2014 has never crashed for me either, and I downloaded it the same day it was a available for general release. So my vote is 2014.
As for FTM vs Ancestry, to me they have different uses. For me, FTM is where I go when I'm working with sources outside of Ancestry, or trying to add media items because then I'm not slave to how fast the site wants to update / refresh whatever. When working with sources inside of Ancestry I'll use the website, and if I'm trying to navigate around my tree to look at something, let my mind wander finding new questions to answer, or showing someone my work. Ancestry is just easier on the eyes, as it were.