Andrew W.wrote a review of UltrAspire UltraViz Spry Hydration Backpack on March 24, 2015
Familiarity: I've put it through the wringer
I have numerous ultra-running vests, from Inov-8, camel, and UltrAspire... and when I'm headed out for a 18-30 mile run that will take me into or out of the dark this is my go to pack. Its light weight is incredible but don't let that make you think featureless. You'll never be wonton for visibility with this kit on. Easy to add additional visibility devices/clip lights if you are on remote trails or busy roads. For the runner who thinks decisively about what they want to carry this pack holds what you need w/o frivolity. I added a 1.0 Liter UltrAspire hydration bladder and it's a perfect all-round vest. Throw a headlamp, two electrolyte shots, and some gels in front stash pockets and you're set for anything. I've run nearly 500mi in mine and I couldn't be happier. The bladder design by these guys is awesome and makes it super easy to fill, empty, clean, and dry w/o it getting funky. Being able to turn them inside out is awesome.
I would say that if you're running more than 30 miles, need to pack extra layers for weather, or need extra gear/ fluid vol > 1.0 L I would go with a my UltrAspire Surge or Inov-8 horizontal bladder vests.
One are I feel could use improvement by UltrAspire would be bladder stabilization. Both my packs w/bladder installed tend to shift and slosh left to right when completely full. A horizontal mounting option or lateral retention devices could be helpful. But as with any pack this is a concern.