Quote - The other reason that the Alpha channel is more effective than the transparency channel for layered materials is that you can boost the Alpha channel intensity beyond 100% (which is 0 on the Vue Alpha Boost Slider).  In some cases, I have used procedural noises to generate the Alpha for a particular layer.  Boosting the Alpha Value beyond 0 will intensify the coverage of the layer without having to adjust the alpha map or alpha noise.   The point is moot if you only want to restrict the Alpha intensity to values of 0 or below - in which case Alpha and Transparency are identical

 

One other thing I forgot to add about the differences between Alpha and Transparency is that use of the Alpha Channel can facilitate layer blending modes, although this is not yet implemented in Vue.  It is reasonable to assume that Alpha Layer Blending modes such as overlay, dodge, burn, screen, hard light, etc.  will be implemented in future Vue releases - just speculating.