I'm going to be the enabler here and say "Buy them both".
I have a 111W and you'll find it's just a workhorse and quite versatile due, as Bob says, to the variety of feet. Also, I think, to the vast number of people who have experience with them and can coach you through learning and troubleshooting.
I have a 22W I need to get running, a twin needle bottom feed. If that 112W is a triple feed, I'd be fascinated by it. How about some nice twin needle decorative stitching on a belt or holster? Woo hoo!
If the twin interests you and you HAVE to choose, it might be the one to get. After all, how often do you see a 112 vs 155?
Somebody was using my 22W as a single needle - they had disabled the second hook.