After two years using my HMG Southwest 2400 pack (black version) it is among the most durable packs I have used. That said the weight is ridiculously high. At 2pounds, that is a LOT of weight. In ten or 15 years, I expect it to be in good shape. But, that durability is associated with it’s weight. A 15oz GG Miniposa has over ten years on it, but has required minor repairs after every trip. The Murmur (2012 model, 13oz) works well in summer months for what I need. Where do you draw the line between a highly durable pack and one that is durable enough? This is like building a house and using one step up in lumber. It really makes no difference for the first 50 years. By then, I’ll be dead…soo, who cares?
Dyneema hybrids are good rugged materials. If I was only 30 years old I could expect the pack to last till I was 80. But, carrying the extra pound or more in weight every second of every day while hiking for 50 years is…well, poor judgement. The heavy duty material clearly weighs more. It clearly is more durable. Is it worth the weight? This is something every individual hiker needs to answer for him/her self.
The jury is still out on the Dyneema Hybrids. A few frayed areas in the packs, means little and a layer of duct tape does well. A good pack is one that will last about 10 years with only minor repairs. Some issues are caused by the hiker: dragging over rocks on an ascent/descent, snagging on a branch and simply pulling it till it frees, offtrail hiking, tossing a pack down 30 feet rather than attaching a rope to lower it, dropping the pack on the ground repeatedly, etc. I ignore those issues because, they COULD be avoided and many packs (even highly touted ones) will sometimes fail. Packs have a purpose. If you go beyond that there might be problems. Hybrids are no different in that regard. But, it really hasn’t been around long enough to state categorically “It is the best fabric for packs.” Indeed, on an SUL trip carrying 10 pounds for three nights, it is likely NOT the best choice.
On my trips with Lean2Rescue, where carrying 20 to 25 pounds of tool weight, my HMG works well. It handles the odd shapes, pointy items (nails) and dense weights (hammer, tape, chalk line, square, saw, etc) fairly well. Would I use the same pack on my UL trips? No. I have no practical use for that kind of durability only carrying 20 to 25 pounds of weight over a well marked and clear trail. I have around 15 other packs to choose from. Mostly, it depends on the type of trip, the overall pack weight, and the treatment it will receive during the trip…no one wants a blown out shoulder strap in the middle of a trip, especially a bushwhack.
Generally, a 5oz/yd fabric is a BIG overkill for most backpackers. For ultralight packers, even 1oz/yd Robic is a bit much. You can get packs ranging from 2.5oz to over 7 pounds to do the same job. But, then again, durability becomes an issue.