I've been trying different harnesses over the past couple years to find what I enjoy the most. Overall, the common theme was magnetic closures which I found to mess with my gps direction way too much. I ended up using another harness with a tension system and it was great, however, the sizing wasn't made for a 12x50 binocular. Then, I saw Vortex released this new glasspak in a large size and I had to purchase it. Overall, I'm damn impressed. The quality is fantastic, its material is very quiet, and it was very well thought out in regards to the tension system so keep the top on instead of letting it flop around. I also like the pockets and their sizing.
I ended up with the large to fit a 12 or 15x binocular but I realize that my 10's would fit in here as well and they aren't too small for the harness. What I found is my all year round harness no matter the size of bino if I'm going between 10-15x's.