I was interested in both cartridges, but rand the numbers through a ballistic app and the .450 Bushmaster had less energy beyond 50 yards than a 150gr. .308.
I just ran .45 Raptor with a 240gr XTP vs a .338 Federal with a 200gr Ballistic Silvertip, and the .45 had a MPBR of 269 yards, dropped below 1,000ft-lbs just past 300 yards, and went subsonic around 450 yards. The .338 Federal had an MPBR of 319 yards, maintained 1,010ft-lbs at 625 yards, and didn't go subsonic until 975 yards.
As cool as those big bores seemed to me, they ended up just not making enough sense when there were easier to acquire, and cheaper, options that were superior. Not to say they don't have a place. They just don't in my hunting.