Oh dude, this is my time to shine, please listen to my story. I bought my volcano about 18 years ago after watching this really stupid TV show that had a segment about the best way to get stoned. They said something like joints get you 25-35% of the THC, bongs are 55-65%, vaporizers are 85-95%. I said shit, I'm not giving up smoking weed any time soon so I might as well invest in my future. I bought it for like $450 at a sketchy open market in LA. I parked the Porsche I was driving behind a bunch of men in cowboy clothes drinking beer on their pickup truck in the middle of the day. Everyone was super nice and my car still had all 4 wheels when I returned.
The Volcano is fucking great. You can see how strong your dose is going to be, there's no smoke, it cools down in the bag, it never irritates my throat, and when smoking with people everyone gets to hit fresh greens from the bag. The thing is built by the Germans so it's a fucking tank, and not the kind that freeze up in the Russian winter. In the 18 years I've had it, the only thing that broke is the air switch that was easily and cheaply replaced and one screw rattled out and disappeared.
As for efficiency, I bought a large ziplock bag full of weed in February of 2018. After sharing a lot with friends, I finally ran out like 2 months ago. For those too stoned to do the math, my volcano made my bag of weed last for over 5 fucking years. I would easily make 1 bowl last about a week before packing a new one, smoking once every day.
I can't recommend the Volcano enough. The only downside is that it's not portable and you have to wait 6 minutes for it to heat up, but that's never been an issue. I bought the Crafty from Storz & Bickel too and it's really great for a portable device. Please take my advice. Save up the money and get yourself a Volcano, you won't regret it!