bluebunneh: The inconsistency is pretty much with most e-cigs, I've found. Most say to get consistency, you need a battery modded e-cig which means one that looks nothing like an analog. I have a 510 and it's the same way. Some hits are bliss, others piss me the @#$^ off.
I've never tried a high voltage battery mod but there are some that say the higher voltage causes you to have less flavor but more vapor and throat-hit. Some say it's better. Who knows. You can possibly hurt your atomizers using high voltage though. Yet, again, some say they burn through them in 2 days, others, 2 months. There are some that are not high voltage but give better consistency. The most popular are:
Screwdriver (SD) - Most popular. Consistency is its specialty most say. Normal voltage.
Prodigy - This is a new product. I believe you can use either normal or high voltage depending on which type of batteries you put in it.
Janty Stick - New product as well. Some say its pretty good for a commercial battery mod. I have one on order. Hasn't come yet. We shall see

Not high voltage as far as I know.
GG - Don't know much about this one but you could look it up on the forums.
The Magnum - This is a DIY mod. High voltage.
Hope that helps you.