Regardless of trap brand, in the past 41 years, I have seen where too many otter have been hip caught, and pulled their way thru and out of the trap. Most of these happened in the old-style square-corner traps that were available in the late 60's thru the late 70's.
When the magnum design traps came out I was sold on them, and still am. While I use a lot of 280's, and like them, I am not adverse to using 330 mags for otter. With the triggers worked over, and properly set, they will get the job done, sometimes two and three at the time. I have never lost a otter out of a magnum-style body gripper.
I acquired some Belisles this past season, not a lot, but enough to give them a fair try, and I realy like them.
Except for my older traps, it's Magnums all the way. Eventyally, when I have acquired enough magnums in various sizes, I will probably put the old timers in some fund raising auctions.