The 101 comes in two styles, one has the controller built in and then it needs to be in a cabinet with the special knee control. Since my husband has worked on both, while the 201 is one of his favorites, the 101 he considers one of Singer's worst ideas. I think Singer must have agreed as they greatly improved things with the 201.
I wanted mine specifically because I wanted the special cabinet setup that it goes with. Parts can also be harder to find as there were so few of them.
It's very neat to have an example for a collection - sort of like having an Edsel in a car collection. Of all the older Singers, I think it's near the bottom of my list of what I'd recommend to someone as a regular sewing machine. while the 201 is nearer the top.