I am prepping for a 100 mile trail ultra. I have run with this pack for 3 hours at a time carrying the filled bladder and two 22 oz bottles of water. No bouncing, no chafing. This vest is fantastic.
Very comfortable and chafing free even after 7 hours of trail running! The water storage capacity is large, and the inner tank is insulated, which will not make the water have a chemical taste.