Oh man there are so MANY of them, it's hard to pick a favorite.
I can vape in my house,,,,,,,no need to go outside,,,,,,,
I can vape in bed,,,,,,,,,at 2am,,,,without turning the light on,,,,,,or even sitting up.
I and my stuff does not stink.
the cost is so much less
the health benefits are so much better
No need to worry about anyone near me and second hand smoke
cool toys to play with

a fantastic community of other vapers
no nicotine stains on me, my teeth, my walls, whatever
long car rides no longer present any problems with nicotine withdrawl
my car windows stay clean (god I hated nicotine stains on my windows)
I could probably go on and on and on,,,,,,,,
but I guess my favorite one is being able to vape in my room whenever I want without bothering my husband.