Miles used to date: 350(approx)
(Note: The gray pouch is not stock, I had customized my pack*)
With the start of all the long trail runs I needed a new system of storing my food, rain gear, first aid kit, survival gear and water. The bag does not feel as heavy when you strap it on since most of the weight is close to you're body.
BOA® (The mini black circular knob on my left shoulder, the red thing is a whistle)
This is actually not new technology, for those that remember the lace-less tennis sneakers from the 90's with the clear fish string...yeah same thing. Click in, and turn to tighten the pack and water bladder, pull the knob to release. The company (http://www.boatechnology.com/) has been growing their product line-up to all sorts of gear, My Mountaineering Boots use the same technology and love them! (reviews for my boots coming soon).
50 oz (1.5-L) Source® hydration reservoir with magnetic clip
The new bladder system holds 1.5 liters of water and does not use the leaky twist cover but a new hard zip lock. No leaking and noticeably less water/bladder movement. My favorite new feature is the magnetic clip that secures the nozzle from swinging on your run.
The only major problem I had so far is the chaffing of certain shirts when wearing it with the pack. So far this seems to only effect the shirt with the Minerale fabric technology (Carob/bamboo wicking technology), After only 15 miles the shirt was falling apart from where the pack attaches to you (chest and shoulder). At the time I was wearing the North face ULTRA GTD 1/4 ZIP, which is actually I great runnning shirt for those that dont use a pack. (Northface is aware of my findings)
Pros: New Boa system keeps things from moving (water too), Not too heavy feeling when on your back,
Cons: Pricey, Needs more straps and pockets, Will chaffee certain shirts (for example Ultra GTD 1/4 Zip)