@b1 After many years of experimenting with them I have come to prefer disposable ones, specifically geek bars. They have tons of sucralose though and may have some peculiar side effects. I would experiment with different types, never buy the RAZ ones, Juul is pretty good.
Refillable vapes can be very well manufactured like the Orion brand, however it's something that you have to take better care of, not break it or lose it otherwise you have to spend a lot more money. Kind of feels good to throw away a vape after it's got 20-30% in the tank and just get a new one for $20.
These vapes last me a very long time, because of the high nicotine content I use them sparingly, and they are perfect for indoors usage as well as after meals/drinks.
I wish I didn't have to rely on nicotine but as John Daly said:
"I believe nicotine plus caffeine equals protein".