In a continuing effort to dial-in hydration & more for ultras, I re-visited the concept of a vest. I had previously tried a different vest and returned it, primarily due to sloshing and bounce of partially-emptied bottles. I used this vest for the first time in a 50 miler this weekend (knowing the best time to try new gear is during a race!). This TO vest, with the soft-body bottles worked really well. As it empties, the air can be squeezed out. Vest-bouncing was minimized and bottle sloshing was eliminated entirely. The soft "body bottles" are definitely the way to go. Until they aren't. One "escaped" during the first miles of the 50 miler when it bounced out of its pocket. Two things, one I had not cinched it in properly, as I was using vest for first time (user error). Secondly, I was in a single-track conga line. The person behind me didn't have time to react and stepped on my new bottle. This fractured the rigid plastic opening so that it would not hold liquid. I emptied it out and continued the next 47 miles with just the one functional bottle.
In summary, this was the first vest I liked while racing, because of the bottles, yet I'm subtracting two stars for the same bottle. I understand humans weigh a lot, but having it break so early in the race on a very giving mud surface was a bit surprising, so I'm giving the pack 3 stars overall.