1. Bowl size: While the volcano bowl is definitely larger, the minimum amount of weed used can be so tiny by just using extra screens on the mighty while sandwiching the weed in the volcano chamber. The volcano wins in party style, when you want to extract a huge amount of weed at once. Both vapes can vape 0.1g without problems.
2. Convenience: While you have to wait for your volcano ballon to be full (VRRR fking loud) and then can transport it through the house, your Mighty is in your pocket at all times, can bet put on without looking and sends a vibration to inform you that it's hot. Also the bag makes noise which just sucks while watching tv on a normal volume. Mighty is silent, only vibration from time to time.
3. Heat-Up time: while the mighty gets so fking hot quickly, the volcano takes at least 2x the time. I'd advise in keeping the volcano on during a session while the mighty should be turned off between draws to preserve battery, if you let it run by cord, it doesn't matter.
4. Vapor: The Mighty has an auto-shutoff function so you won't lose a big amount of cannabinoids. With the volcano you have to finish a bag in 5 minutes or it becomes way to harsh. People are like "the vapor can be hold for hours in a bag" - yeah, but that isn't fun anymore. Adjust your size of the bag to your most likely consuming style. I tend to make the ballons just to large and then had to lay it away after vaping too much, giving away precious thc.
5. Miscellaneous: The 3metre party ballon is something you should try out once.
The Mighty's function of getting oil from the cooling chamber is fkin awesome. I never washed out a old volcano bag but am scraping my CC almost after every use to get free oil and keep the CU clean.
Which gets us to the point of
6. Cleaning/Maintaining: I had my volcano for 10 years and besides getting new ballons from time to time, the only thing I had to replace where the 15€ part of the valve and the 5€ clench that grips the ballon to the valve.
On a Mighty you should often clean the cooling chamber or after 5g you can't almost draw anymore. On a Volcano you should clean the sieves but you don't have to do it that often.
I'd buy a mighty over a volcano these days just because it is cheaper, more portable, more silent and because you don't have to watch over any ballon-filling-procedures. But still, I love my old cano and it is my 2nd favorite vap I own (1. Mighty 2. Cano 3. Solo)