I have been using the Ultra Vest for over a year now, and it’s by far the best running pack I’ve ever used. I use it on everything from daily run commutes to work and back (plenty of room for a change of clothing and all other essentials), to day-long ultra’s (more than adequate water-carrying capacity, with ample room for other essential gear, food and phone). It also compresses nicely for shorter races which have minimum kit requirements. No matter how much stuff I carry it never feels heavy, and has never given me any chaffing or other problems. After a year of good use, it’s still in great condition, with only the odd rinse required after a particularly sweaty or muddy race or training run. I’ve even used it on a road marathon where I preferred to carry my own water than rely on plastic sachets and did not feel in the least encumbered.