This may be an odd way to describe it, but one of the biggest differences IMO is that the Storm models are designed to have a whole lot of traction, from the TrakTec inserts on the handles to the aggressive thumbstuds, while the Shallot has a noticeable lack of sharp edges and rough areas, with no thumbstuds and relying on terrific ergonomics to give you a good, solid grip. I think the Storm would be a good hard use knife if you were wearing leather work gloves. The Shallot on the other hand, which has been my favorite EDC the past several months, is a smooth, sleek and sexy performer that's equally at home in the front pocket of dress slacks, jeans, or summer shorts, and doesn't tend to tear up fabric or the skin on your hands.
It's also worth mentioning that the Shallot has a very subtle recurve compared to the Storms, which I find much easier to sharpen -- the Shallot sharpens readily on a regular benchstone. Also the SpeedSafe action of the Shallot is very robust, much more energetic than the Leek for example.
Both are high quality knives with a great blade steel. And they're both Kershaws, which means you're getting great quality and value from a company that takes its customers' satisfaction seriously. So it's really a matter of personal taste ... I personally like the Shallot a whole lot, but there are knowledgable, veteran knife users posting here who've said a lot of good things about the Storm.
