I have had my Provari for just over a week and I love it! I went with the mini and didn't bother to get an extender cap. My thinking is that I would rather have a smaller MOD and carry an extra battery or 2 (or3) around with me. I vape quite a bit and I am finding that I burn through 2-3 18350's a day on it.
Also make sure you have nipple top batteries, flat ones won't work in the Provari.
I am sure you are going to be super happy with yours!