120's stabilize a lot easier. No doubt they are stronger and if I'm buying traps I'm going to buy the 120s. (I also don't trap rats and very little mink). But I've got some 110's around that I've had since I was knee high (first traps I ever bought myself were a dozen Victor 110's when I was 8 years old, saved up money from selling fur I had caught in hand me down traps to buy those. Had to carry a rope and a homemade safety around with me to set them) and I've never had a problem with them. Every time this comes up there are several people who point out how inadequate they are for marten, and how they will cause fur damage. Maybe, but I've caught quite a few in them over the years, and they were all hanging there dead and no signs of excess struggle, nor any fur damage. I've never had a fisher stick his head in one but I suspect they would be underpowered for them and you would get some pullouts or live fisher. Which wouldn't be a bad thing since we aren't allowed to keep fisher, here.
I don't use my 110s much anymore. If I'm setting a for a mink maybe, if I am using my 120s for marten at the time, but 120s are easier to stabilize, so I'm liable to grab one of them for mink. Caught a marten last year in one, had an old box with a very narrow spring slot on one side, made for a specific brand of 120 and I didn't have one of them along when I was setting so I threw a 110 I had in the trap box in there. Switched it out when I caught the marten, but as usual, it seemed to kill just fine and no fur damage.