Just fired mine up last night for the first time.
After reading all the posts on these, I was expecting it to be louder than it was. When it was heating, all there was was a slight hiss. With any kind of ambient noise outside, which there always is, I don't think that anyone further than a foot or two away would be able to hear it.
I wanted to see how efficient it "could" be, so I loaded 2 PD bowls worth inside the IO and got about the same amount of hits that I get off of one PD bowl with the PD, so, from an efficiency standpoint, it looks like I would use twice the amount of weed with the IO than I do with the PD............but man, for a portable, there's nothing better.
The other thing is how evenly it vapes the herb. With the PD and the VG, I get various shades of brown, but with the IO, ALL the duff was vaped evenly to a very dark brown without having to do any stirring or refilling.
The fins do get a bit toasty. I've seen video's where the users just kept the fired up unit in it's case while hitting it, but I'd be afraid of it overheating. Do ya think that's a valid concern?
This puppy isn't going to get a lot of use, being that I mostly vape indoors, but for those times when I'm out and about, this is a winner.