Rating: 5 / 5
This pack has been so comfortable that I considered downgrading my other pack reviews to allow valid comparisons. Zpacks has made some changes to the Arc blast since I bought mine last year. I'll cover them and give my opinion. This evaluation is based on 400 miles on the AT and observations of another pack I saw that had about 1800 miles on it. Zpacks rates this pack for 30lb. and that's where I found it to start getting uncomfortable, but I started a few hikes with 35 lb. and it wasn't too bad. Zpacks also says the pack is good for one AT thru hike. Based on the one I saw with 1800 miles on it, I'd say that's about right. The ultralight cuben fiber material was fraying significantly by then, especially on the shoulder and hip belts. My own pack is showing wear on the bottom and side pockets. I added the optional lid, two belt pouches and a shoulder strap pouch which upped the weight from stock 15 oz. to 20.4 oz. The pack comes with a capacious stretch net front pouch good for storing rain gear, fording slippers etc. for easy access. The stock pack also has two side pockets. I stored a 1.5 liter water bottle on each side also my soap and fuel in them. I don't like to store liquids inside the pack for obvious reasons. The lid was smaller than I'm used to for a lidded pack. On the other hand, the belt pockets were the most capacious of any pack I've owned and they're repositionable, a feature that also makes them the most accessible belt pockets of any pack I've owned. The pack frame is comprised of two carbon fiber stays linked together by another stay in the middle. The new model has two links. A net stretches over the frame which when properly adjusted affords an air gap for ventilation. I stored a sit pad in the gap. My pack isn't waterproof. The new model has taped seams. My pack has side compression straps and bed roll straps on the bottom. The latest model replaces the straps with cord and cord locks. The pack is so comfortable because the frame is very effective at load transfer and the shoulder and hip padding is more than adequate for the rated load. The only flaw I experienced was related to the bed roll straps. They tended to loosen. They actually dropped my hammock one one occasion and I was fortunate to notice it immediately. After that I added a lanyard to the bed roll so it would drop against my legs if it came loose again. It didn't but I reported it to the manufacturer who said the new straps and cords would fix the problem and he offered to replace my straps gratis. The two other light weight packs I've owned are an Osprey Exos 58 and a Gossamer Gear Mariposa. The Arc blast beats the Mariposa hands down for comfort because it is more effective at load transfer. For convenience features they're about the same. The Exos exceeds both for convenience features but it's in between the two for comfort. For overall comfort for hikers who are willing to give up some durability and can keep the weight under 30 lb. most of the time, this is pack is an excellent choice.