I've used each of the vaporizers that you've listed except for the Zephyr Ion. Out of all of the ones you listed, I would definitely suggest the V-Tower Extreme Q. It's my go-to non-portable vaporizer, and even though it's only half the cost of a digital volcano, myself and everyone I know that has used both prefers the V-Tower. Additionally, the V-Tower allows you to use a bag or whip without any additional attachments.

Bottom line - the V-Tower is a better vaporizer for half the money.

If you have any specific questions about the V-Tower or any of the other vapes, just let me know and I'll try my best to answer them for you.

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Check out my Iolite Review and my Portable Vaporizer Comparison page