I didn't like the hand held vapir when my friend let me use his. It's okay, it's just clunky and I don't care for the disk system it uses. However, I only got to test the Vapir One 5.0. Not the newest model.
The Volcano is good, but IMO, the Extreme Vape is a way better value. It's what I currently own now. You can use a bag just like the Volcano, but you can also use a whip. I also like that the mouse piece on the Extreme is glass, not plastic like with the Volcano. It also comes with a remote, has a built in timer, and lots of little accessories like an aroma bowl for 'essential oils.' It uses a ceramic heater just like the Volcano and also has digital controls.
Eventually the bags and whip will need to be replaced. With the Extreme Vape, you just use XL Oven Turkey Bags. The tubing you can get at Home Depot for $3-$5 for 12'. It's the exact same food grade quality kind too.
I've had mine since Jan 09 and it's still runs great under heavy daily use. It's outlasted three glass bongs, and two other vapes that I've had. If mine ever breaks I'm buying another one the next day. It's that good.