I have 3 Supernovas and 2 vm100. The Vicmarcs are better, but I don’t know that they are enough better to justify the cost. Do you already have jaws for Nova chucks? It is nice to stay with on line so you can use jaws and keys interchangeably. 

Also, the vm100 is great unless you end up making pretty big pieces. I am pretty sure the jaws are not interchangeable between the vm100 and 120.