Well I have a first hand experience on a hog hunt with both guns. February two years ago three friends from work and I went on a trip. One fellow, who had never hunted or shot anything but paper, had a brand new .450 Marlin Guide gun, another guy had his .300 win mag, and I brought my Buffalo Classic in 45-70. We were blessed to get into the hogs within the first hour of daylight. The guy with the 450 shot first

, that gun was brutally loud! The magna porting magnified the volume, no pun intended. I was the second to shoot, bang flop, and the guy with the .300 shot, bang flop. All three calibers did their jobs, but all four of us walked away with chimes in our heads from that 450. I'm not recoil shy, and gun fire is music to my ears, but excessive noise is another matter. For close work, which hog hunting usually is, I would not buy a gun with magna porting.
Either caliber is good. The 45-70 has many more load levels and choices and ammunition is more available. Until the 450 becomes more mainstream my money goes to the 45-70.