I've been searching a long time for a medium volume vest style pack that will allow me to run with clothing and/or gear without it bouncing all over the place. This is the best I've found at this size. I have the Duro 6 as well and use it nearly every day for short to medium runs in the warmer months when I don't need to carry much. The Duro 15 really shines when my needs exceed running trails for a couple of hours. The 15 holds a liter more water than the 6, adds hipbelt pockets, and can manage a minimalist overnight or two if the nature of your gear will allow it (read: compact, lightweight, high quality). The pack moves with you when you run, it's organized sensibly, and I can fit my phone in the front zipper pocket with room to spare (iPhone 6s). I'm pretty hard on my gear and it's held up well to frequent use. Possible cons or tradeoffs if you're considering the pack: no pack cover, dual chest straps are a little high maintenance (though you do get used to them after a while), main shove/stretch pocket straps must be undone in order to access the three zippered compartments in the main portion of the pack. It can be hard to slip a full reservoir into the pack when it's full of gear (the bladder is not rigid), so make sure to fill it first, then pack up. Note as well that as you run and drink and empty the reservoir you must continually cinch the chest straps, because the volume of the pack overall shrinks and it will start to bounce and slosh if you don't stay on top of it. But this becomes intuitive after a while and is hardly worth mentioning. Lastly, it is possible to carry a small laptop if you have a svelte case of some sort to slip into the main compartment - there's no integrated sleeve or anything specifically designed to hold something with a screen, but I do it all the time. Basically, between the Duro 15 and the Duro 6 I have about 95 percent of my needs covered if I want to run trails and carry a bunch of stuff.