I just have to say once again how freakin' excellent the adjustable voltage is on the Buzz. I use 510 cartos almost exclusively, and the 'fine tuning' I can do between flavors / cartomizers is easily worth the $115 price tag of the Buzz within itself.
If I'm using a darker, coffee flavored liquid, I just dial it down 1/2 turn. If I'm using a light-colored 'soft' flavor, I just turn it up 1/2 turn. The fine adjustments honestly bring my level of enjoyment up to a whole new level. I'm a full-on perfectionist, and this thing quenches my soul. ;-)
I'm just not sure how I could ever live without variable voltage control from this point forward. I'm sold and converted. The Buzz totally rocks.