I think what your fiends are experiencing is purely psychosomatic. The power of belief is an incredibly powerful tool, if they are able to convince themselves that weed is more pleasurable when mixed with cigarette tobacco, then for them it will be.
Personally though I think cigarette tobacco tastes like shit and cigarettes are much more expensive than rolling tobacco; hence I roll my joints with rolling tobacco. Plus rolling tobacco burns slower than cigarette tobacco, so your joint lasts longer.
