First of all, the amount of wear on the mouse will affect the tactility of the click. I've compared new and old deathadders and the differences in response almost makes it feel like a different mouse.
Yep. I believe a lot of razer mice have this problem. My abyssus was gently used for 2 months but the left click started being noticeably stiffer than the right click. It is somewhat annoying. Razer mice tend to use the body-is-the-button design as well and where you apply pressure on the mouse will also affect the kind of tactile feedback you get.
Secondly, the materials used in the Black Edition top makes the click feel different. I've experienced this first hand when I took my Deathadder 3G V3 internals and placed them in a Black Edition shell. The clickyness did feel different because of the materials used in the shell.
I believe this is because of the body-is-the-button effect. The tactile response varies on the shape of your mouse and the material used for the top plate.
Think, the Steelseries Xai, Deathadder, G400, and MX518 all use the same switch yet they all feel different.
I believe they all use omron switches. The CM storm uses it too and feels more tacticle than the above because it has separated, distinct buttons for left and right click instead of using the Chassis. Switches are important but trying out the mouse itself is even more important as they tend to be more (or less) than the sum of their parts.