You guys and gals are so perceptive and catch all the details that I often miss! Our Outdoor Retailer roundup articles are meant to highlight new products of interest so readers can keep up to date on new products hitting the market or in the pipeline. Its hard to be comprehensive under the constraints of limited time and sleep depredation at Outdoor Retailer. That said, here are some responses to your questions:
Osprey Exos Packs: When one first looks at them, a first reaction is that the suspension system is not padded enough. But after using them it turns out not to be a problem. The frame wraps around your hips and the padding is sufficient to carry a moderate load comfortably. The trampoline backpanel on the Exos gets it just right. I can feel it press against my back, and it ventilates very well. Previous designs had too much space behind the mesh, which reduced usable pack volume and pushed the center of gravity outward too far. The Exos 58 and GG Vapor Trail are about the same weight and volume, and I would personally choose the Exos because I like all the pockets and convenience. The Vapor Trail has GG's cushy suspension system but lacks most of the features of the Exos. Both packs are most comfortable with moderate loads (<30 pounds), but are capable of carrying heavier loads for a few days when needed.
Z-Packs: You caught me on this one; Z-Packs was off my radar screen because the business was on hold last year while Joe hiked the PCT. His new Blast packs, available in 3 sizes and made of Cuben Fiber, are indeed remarkably light, and the only Cuben packs currently available. Joe Valesko at Z-Packs is a great guy who makes great gear at reasonable prices in support of thru hikers and I highly recommend him.