How would you like to make that decision every time you go out to hunt/shoot, the Fox or the M21. No sir. I wouldn't want to be in your shoes!!
The 21 will weigh just over 8 lbs and the Fox weighs 6.5, which one would you want to carry around in the grouse woods all day??

I hope to use it on some waterfowl though. I ended up selling all of my English/continental guns to have only a custom 2 bbl/gauge Fox for hunting and a custom 21 for clays/waterfowl. Due to my size, I needed a custom gun. I also kept a nice vintage hammergun to use occasionally as well to add some nostalgia when desired.