I got a V6 version yesterday and wore it while jogging (which for me means lifting my feet above a walk) for an hour. The additional stiff layers kept the material away from my face during heavy breathing which is nice but moisture did build up. Several times I had to take the mask off and let it hang from the lanyard when nobody was around. I think any mask that doesn't have a vent will tend to have moisture build up, especially during cardio exercise. That's why I exercise without a mask, away from other people.
I can see how some folks perceive this mask as more breathable. I'd say that's because the extra layers keep the fabric away from the mouth. I like this aspect of the mask but unfortunately I'm having a heck of a time keeping my glasses from fogging up. I think the thick layers near the nose makes it almost impossible to place glasses in a comfortable position and keep fog from forming. I changed the nose wire but that hasn't helped.
My favorite mask is still the V2. It works well for me since I don't need to wear a mask all day and only use one when going to the market for short trips. It fits well and accommodates my glasses. I rarely have problems with my glasses fogging up when I wear that mask. The adjustable ear loops makes the fit comfortable and the lanyard keeps me from forgetting or loosing the mask when I take it off while riding in my car.
Thanks to the TB crew for posting the pattern for these masks. I've made a couple dozen V2 masks for my family and they love them.