My example of this jacket is a couple of years old and has performed very well, with the slight exception of some delamination issues that were handled under warranty. While the performance of the fabric rates five stars, some of the details of the jacket (the bizarrely unsecured hood drawstrings that protrude like alien antennae, for example) are not executed to the standard expected for a "hoody" costing nearly $400.
The main reason for this review, though, is to alert readers to the relative delicacy of the Power Shield O2 fabric. Some reviewers have referred to experiencing a wind resistance of approximately 50%, which is significantly less than Polartec's rating of about 92%. This leads me to believe that at least some users have been machine-washing and drying their jackets.
This might be fine with other versions of Power Shield, but Power Shield O2 has a perforated membrane, which makes the fabric more breathable. You don't have to be a materials scientist to realize, though, that a perforated membrane is not as tough as the regular Power Shield membrane. THIS FABRIC CANNOT BE MACHINE-DRIED - at least not if you want it to retain anything close to its intended level of performance. The cryptic symbols on the fabric care label signal that the garment is to be air-dried, but many people either don't read or understand the symbols or simply assume that this form of Power Shield can be treated the same as others they own.
The Hyllus (formerly the Hercules) Hoody, even with its exorbitant price, offers more performance per ounce than almost any other hoody on the market, but that performance can be instantly and permanently compromised by improper care. Arcteryx and other manufacturers should take the simple and inexpensive precaution of providing a little pocket card with new products to give explicit (rather than symbolic) care instructions to prevent their customers from inadvertently ruining the performance of their new outdoor clothing.