I have, at the moment, the Arizer Solo and I love it although it is listed as a portable it is more of a at home vape due to its size and having a glass stem that can easily break, it works like a beast and is a very solid unit. My buddy in SF, well a few of my friends, have the PAX and the PAX 2 just came out and both are great vapes probably two of the best on the market right now. My buddy in SF also has the Crafty by Storz and Bickel the maker of the volcano which he has the digital volcano as well. The Crafty is expensive but ranked as the top portable as of now but we shall see with the new Reviews that will be coming out about the Grasshopper.
My rating for portables would be:
1. The Crafty
2. The PAX 2
3. The Mighty
4. The PAX
5. The Solo
6. The Air (Made by Arizer who makes the Solo which I have, it is a remake of the Solo so it is thinner and comes with shorter stems thus making it more portable and comes with a silicone sleeve for any heat issues you may have while holding it)
The VaporWizard reviews all of them and you can check them out on the link I posted.