The charge of the battery is a factor, too. When I used to use the cheaper batteries (when I first started vaping), throat hits would decrease or disappear a few minutes before the battery died and needed to be recharged. After I recharged the battery, the throat hits would be great again. I've read that the main factors are the amount of PG and the strength of the nicotine (if the battery has a good or full charge, too), but I'm sure there are other factors. In my experience, the amount of vapor produced has no bearing on throat hits. Also, when using cartomizers, I get better throat hits when I let refilled cartos sit overnight. I think letting the liquid soak in thoroughly is a factor.