It is built like a tank. Personally as long as you build your kayfun 1.2-1.8ohms you are good on the provari. Its build quality is top notch, cant really fault it. Has a warranty, easily repairable. Able to change batteries easily. Choose a color you like and if you get tired of the color just get wraps for it lol!
It is only you can decide on what to do with your money

if you like it then get it, that is my rule though. Am over those sleepless nights thinking about these things haha! If you dont like it you can always sell it with a minimal loss. Youll get posts about the provari's pros and you'll get its cons as well. As ive said, its only you who can decide.
Alao as ive said before, it has its limitations as well.
If you do decide to get one, i advise to get the mini as it is easier to make it longer and you cant really make the standard shorter :O