HiDave,
To answer your question, I think you need to look at the whole picture. The DeWalt 18v flashlight uses an 18v rechageable battery $80) and a charger ($50). That $35 light is now $165. As you may already know, the flashlight is one of the many "tools" in the DeWalt cordless tool program along with drill, sanders, saws, etc. So, if you already own one of these tools, you can use the battery and charger.
The flashlight is bright and the total light output is much greater than most. Keep in mind, the light is intended as a work light, and does not have a concentrated beam. I have one in each of my 3 work trucks, and I keep one in the garage on the workbench. I am in the building trades, and the flashlights were a "free accessory" with the purchase of a $500 tool kit (2 saws + 1 drill per kit). How free is that ?? $1500 $$
I don't think there is anyway you can compare this light with any of the SureFire products, they are completely different kinds of tools, with completely different intended uses.