I own both. I do favor the WW coat. I wore both guiding off horseback last season. Even the outfitter and other guides who are all Filson guys admit it's a better coat, at a price.
I am holding the 2017 Filson Double Mack now. There is no way it matches up to the 26oz fabric weight. It is clearly thin, and in the light appears like gauze. Holding the WW up it is surprising they advertise it as 19oz when it is thicker and heavier than the Filson fabric. The truth lies in the middle, Filson as of 2017 is definitely cutting corners, WW is possibly understating.
The Filson has way more pockets. I can get almost 3 times as much stuff into a Filson as a WeatherWool. It is also a fact that Filson front pockets have less retention than a zippered pocket. I am careful to put larger items into the pockets and I have to watch myself if I bend over or clamber over things with just a snap holding small things in. I lost a mushroomed bullet I retrieved from an elk for a client, I believe out a Filson pocket. Entirely my fault but I kinda blame the pocket design too.
Zippers and elastic do fail, but they can also be replaced. I prefer to have buttons too, but the zipper underneath a full set of buttons is game changing when riding into a strong headwind.
Filson I think is using NZ loomed fabric. It is decent fabric, but it is indeed scratchy as hell. It's a logger jacket, I should

less, but it is indeed scratchier to skin.