2 extremely different knives. Why are you looking at these knives? Just to have one? EDC? food prep? Skinning knife? I imagine your just looking at them because you like both of them and dont have a role in mind. In that case I cant really tell you what to get. 940 will be quicker, smoother, go with you more places, less scary, easy one hand operation, something you will want to use in many roles. The onslaught while only having a half inch bigger blade is much more cumbersome. Its not bad or sloppy in any way, just larger and will probably be used less in every day roles. Can operate one hand but not as quickly as the 940. Just a beefier, scarier knife, although I think blade thickness is similar.
Since I live in Jersey and still in college I would go with a 940 (which I actually almost just bough, went with Alias instead). The Onslaught is a much bigger package for only a half inch extra reach.