I would not let the non-removable battery steer you away from this device. It charges relatively quick. From a dead battery to a full charge, most report about an 1 hour to 1-1/2 hour charge time. It is very pocketable as I often carry it in and out of my office in my pocket. You will really get to taste your flowers with this vaporizer.
@darkrom Maybe this will help you decide as I feel I was in the same boat as you. I too am waiting on a Zion and my VAS was killing me last month since the delay started and it was my birthday two weeks ago even. I bought 3 portable vapes last month. First, I bought the miVape by impulse to make sure I had a new vape on my birthday since the Zion was going to be delayed. I wasn't too impressed at first but I see it being a great session companion for the Zion if they get the mouthpiece and capsules redesigned. I already had the ESV at this time and was enjoying both a lot but still I felt that my VAS for the Zion was not cured or sustained even. Unfortunately before I could really give the miVape much of a chance, it and the ESV were taken by servants of prohibition. This was kinda devastating in that it left me with only the Daisy as a true convection device and I really don't like conduction. And it was 6 days before my birthday so I had to act fast. I saw the FW3 go on sale on its website the next day and jumped on it. I hemmed and hawed through the weekend about whether or not the FW3 would be able to fill the shoes of the ESV. I wasn't even thinking about the Zion anymore because going from an ESV to a Solo is a pretty dramatic change. I just needed to get back to ESV quality and so Monday morning (2 weeks ago) I bought an ESV. After having both the ESV and the FW3 for over a week, I can say I am glad to have both and they together will sustain my VAS for the Zion. I pre-ordered my Zion in August so I know I have a wait. I also know it won't be so hard.
The big differences between the ESV and the FW3
for me are-
Both the FW3 and the ESV provide tasty vapor, however the ESV provides a cool vapor that is almost refreshing while the FW3 provides a warm vapor that leaves a slight irritation for me on my throat. In the winter the ESV is absolutely amazing because the body gets so cold if you leave it out in your car or in your pocket while out in the snow. The FW3 allows for temp stepping and provides more hits per capsule than the ESV does per chamber load. I find the ESV extracts faster and although you can use it to temp step, I find that I don't because I can get the ABV pretty even and dark to an almost blackish color on the lowest temp setting.
I think most of the other differences are minimal and don't really separate one from the other. The cleaning is minimal with both and takes little time when you do need it. Both give big tasty clouds with no effort required, just draw. Now with all that said. My advice for you would be to go for the ESV. That price may not stick around and the FW3 price is not going to change any time soon. I doubt the ESV will collect much dust when you get a Zion. The Zion just isn't suitable for all occasions. It's like my Daisy. She's portable but I'm not going to carry her around town with me. I don't see the Zion leaving my house much...do you?
Also, I still would get it from Vapornation over the vape-smart website and get Vapornation to match the price.